Change search
Refine search result
12 1 - 50 of 74
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Al-Ayish, Nadia
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    During, Otto
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Silva, Nelson
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Gudmundsson, Kjartan
    KTH Royal Institute of Technology, Sweden.
    The influence of supplementary cementitious materials on climate impact of concrete bridges exposed to chlorides2018In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 188, p. 391-398Article in journal (Refereed)
    Abstract [en]

    In order to reach a specific service life of reinforced concrete structures a certain cover thickness is needed. At present, this is regulated by national standards that also limit the amount and type of supplementary cementitious materials in different exposure environments. The regulations do not, however, consider the actual durability performance of concrete with supplementary cementitious materials. As a consequence, the LCA results might be misleading. This paper shows the environmental impact of concrete with supplementary cementitious materials in chloride environment considering their specific performances. Prescriptive and performance based service life prediction models for chloride ingress are applied and compared.

  • 2.
    Al-Ayish, Nadia
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Hadi, Mohammad
    University of Wollongong, Australia.
    Neaz Sheikh, M.
    University of Wollongong, Australia.
    Gudmundsson, Kjartan
    KTH Royal Institute of Technology, Sweden.
    Karoumi, Raid
    KTH Royal Institute of Technology, Sweden.
    Environmental impact of concrete structures reinforced with GFRP bars: A simplified study on columns2019In: Proceedings of the fib Symposium 2019: Concrete - Innovations in Materials, Design and Structures, International Federation for Structural Concrete , 2019, p. 1998-2005Conference paper (Refereed)
    Abstract [en]

    Concrete has a significant influence on the global warming due to its high usage in the construction industry. There are a few different strategies to increase the sustainability potential of concrete structures. Most of these strategies involve reduction of the total clinker content. One strategy, which is often neglected due to its complexity, is to increase the durability of the concrete structure. By increasing the durability, the need for repair and maintenance is reduced and thus less resources are consumed during the service life. One of the main deterioration mechanisms in concrete structures is the corrosion of steel reinforcement. A strategy to increase the service life of concrete structures in harsh environment would therefore be to increase the durability of concrete or to use low- or non-corrosive reinforcement instead of traditional steel reinforcement. This paper focuses on the latter. Glass fibre reinforced polymer (GFRP) bars are non-corrosive and have emerged as an alternative to steel bars in reinforced concrete structures in harsh environment. They have other mechanical properties than steel and opens for alternative mix designs for concrete. However, the environmental impact of concrete structures reinforced with GFRP bars has not been fully investigated and most life-cycle assessment (LCA) studies have an exchange ratio of 1:1 between GFRP and steel bars despite differences in the mechanical properties. This paper studies the climate impact of concrete columns reinforced with GFRP bars through an LCA methodology, focusing on the functional unit.

  • 3. Alberg, Ingmarie
    et al.
    Berntsson, Britt
    Andersson, Kjell
    Dannestam, Åse
    Persson Boonkaew, Frida
    (Larsson) Gulliksson, Daniel
    Fält, Jenny
    Good, Johanna
    Tiden, Sophie
    Nordin, Mats
    Claesson, Per
    Åhström, Mikael
    Edwards, Ylva
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Lyne, Åsa Laurell
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Kvalitetssäkrade systemlösningar för gröna anläggningar/tak på betongbjälklag med nolltolerans mot läckage: Rapport- Arbetsprocessen2017Report (Other academic)
  • 4.
    Andersson, L.
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Silfwerbrand, Johan
    KTH Royal Institute of Technology, Sweden.
    Selander, A.
    Cementa AB, Sweden.
    Trägårdh, Jan
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Continuous preventive bridge maintenance in Sweden - Field experiment on the effect of washing on concrete bridges2019In: Proceedings of the fib Symposium 2019: Concrete - Innovations in Materials, Design and Structures, International Federation for Structural Concrete , 2019, p. 1135-1141Conference paper (Refereed)
    Abstract [en]

    Bridges are an important part of the infrastructure. For the bridges to have the longest possible service life with minimum repairs, the maintenance is of great importance. One type of bridge maintenance that is rarely researched is the continuous preventive maintenance. The continuous preventive maintenance consists of removal of vegetation, cleaning of bridge joints and drainage systems as well as high-pressure washing of the structure. The effects of washing is heavily discussed but not properly researched. A study on the effectiveness of washing concrete is therefore being conducted. A field experiment has been initiated where concrete specimens are installed on an edge beam of a road bridge. The specimens are of two recipes where one represents an old bridge with rather high water-cement ratio and the other one represents a new bridge with a low water-cement ratio. 50% of the specimens are washed annually, while the others are not. Each year samples are collected and tested for a chloride profile. The results for the first year of exposure have been determined. They are promising but are still only very preliminary. The effect of washing, if any, will be visible after a longer exposure.

  • 5.
    Appelquist, Karin
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Trägårdh, Jan
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Detection of potential alkali-silica reactivity of aggregates from Sweden2017Conference paper (Other academic)
  • 6.
    Babaahmadi, Arezou
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Tang, Luping
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB. Chalmers University of Technology, Sweden.
    Abbas, Zareen
    University of Gothenburg, Sweden.
    Zack, Thomas
    University of Gothenburg, Sweden.
    Mårtensson, Per
    Swedish Nuclear Fuel and Waste Management Company, Sweden.
    Development of an electro-chemical accelerated ageing method for leaching of calcium from cementitious materials2015In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 49, no 1-2, p. 705-718Article in journal (Refereed)
    Abstract [en]

    To facilitate the long term durability predictions of nuclear waste repositories, acceleration methods enhancing calcium leaching process from cementitious materials are needed, even though mechanisms not necessarily comparable to those predominant in a natural leaching process may be developed. In the previously published acceleration methods the samples are very small, which limits further physical or mechanical tests. In this paper, a new acceleration method based on electro-chemical migration is presented. The method although not driven with the same kinetics as in natural leaching, was designed in such a way that unnecessarily destructive by-effects could be minimized while promoting a higher leaching rate for a sample size suitable for further testing the mechanical and physical properties. It is shown that approximately 1 × 106C of electrical charge per paste specimen of size Ø50 × 75 mm (approximately 230 g) is required to leach out the total amount of Portlandite. The chemical and mineralogical properties of leached samples are characterized by various techniques. It is concluded that aged samples are comparable to those leached in a natural leaching process as both are characterized by a layered system comprising an unaltered core delineated by total dissolution of Portlandite followed by a progressive decalcification of the calcium silicate hydrate gel.

  • 7.
    Blomfors, Martin
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Honfi, Daniel
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Ivanov, O. L.
    Lund University, Sweden.
    Zandi, K.
    Chalmers University of Technology, Sweden.
    Lundgren, K.
    Chalmers University of Technology, Sweden.
    Reliability analysis of corroded reinforced concrete beam with regards to anchorage failure2019In: Life-Cycle Analysis and Assessment in Civil Engineering: Towards an Integrated Vision - Proceedings of the 6th International Symposium on Life-Cycle Civil Engineering, IALCCE 2018, CRC Press/Balkema , 2019, p. 337-344Conference paper (Refereed)
    Abstract [en]

    Reinforcement corrosion is a common problem in reinforced concrete infrastructure today, and it is expected to increase in the future. To simply replace the corroded structures with new ones requires large resources, both in financial and environmental terms. Therefore it is important that existing structures are used to their full potential, also after the onset of corrosion. This paper presents a reliability study of the anchorage capacity of a reinforced concrete beam including reinforcement corrosion. The sensitivity of the different input parameters is also studied. As expected, the results show that the reliability is reduced with corrosion; the magnitude depends to a large extent on the modelling uncertainty used for the bond model for corroded reinforcement. The sensitivity analysis shows an influence of corrosion also on the sensitivities of the input parameters, which is expected based on the properties of the underlying bond model. This paper demonstrates that probabilistic evaluations give valuable insight of the reliability, which can be used to prolong the service-life of existing infrastructure and save both money and the environment.

  • 8.
    Blomfors, Mattias
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Lundgren, Karin
    Chalmers University of Technology, Sweden.
    Ivanov, Oskar L.
    Lund University, Sweden.
    Honfi, Daniel
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Zandi, Kamyab
    Chalmers University of Technology, Sweden.
    Practical bond model for corroded RC bridges2017In: High Tech Concrete: Where Technology and Engineering Meet - Proceedings of the 2017 fib Symposium, 2017, p. 1793-1803Conference paper (Refereed)
    Abstract [en]

    Corrosion of steel reinforcement is a common cause of deterioration in reinforced concrete bridges and many existing bridges are damaged to varying degrees. The rate of deterioration of the bridge stock has been shown to increase due to climate change. Unsympathetically, the demand for load-carrying capacity is however often increased with time. Therefore there is an increasing need for reliable methods to assess the load-carrying capacity and remaining service-life of existing infrastructure. A simple model for the assessment of Anchorage in corroded Reinforced Concrete structures (ARC) has previously been developed. It was originally based on fib Model Code 1990 and has been verified with experiments and three-dimensional nonlinear finite element (3D NLFE) analyses for both accelerated and natural corrosion as well as for different degrees of corrosion. The model was applied when assessing two road bridges in Sweden. The investigation demonstrated great cost savings but also areas for improvement, in particular regarding (a) applicability to practical cases and (b) incorporation of uncertainties in the assessment. The primary focal point of this paper is to present an overview of the development of the ARC model together with recent verifications against a large bond test database as well as foreseen future developments. It was found that the ARC model represents the physical behaviour reasonably well, and gives conservative values of bond strength compared to the bond tests database. In future works, among others, uncertainties of the input variables will be incorporated by means of probabilistic modelling, making way for implementation of the ARC model into semi-probabilistic safety concepts by extraction of modification factors. Overall, with more accurate and reliable assessment methods for corroded RC structures, environmental and economic savings are imminent as more of the potential of existing structures can be realized.

  • 9.
    Blomfors, Mattias
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Zandi, Kamyab
    Chalmers University of Technology, Sweden.
    Lundgren, Karin
    Chalmers University of Technology, Sweden.
    Coronelli, Dario
    Politecnico di Milano, Italy.
    Engineering bond model for corroded reinforcement2018In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 156, p. 394-410Article in journal (Refereed)
    Abstract [en]

    Corrosion of the reinforcement in concrete structures affects their structural capacity. This problem affects many existing concrete bridges and climate change is expected to worsen the situation in future. At the same time, assessment engineers lack simple and reliable calculation methods for assessing the structural capacity of structures damaged by corrosion. This paper further develops an existing model for assessing the anchorage capacity of corroded reinforcement. The new version is based on the local bond stress-slip relationships from fib Model Code 2010 and has been modified to account for corrosion. The model is verified against a database containing the results from nearly 500 bond tests and by comparison with an empirical model from the literature. The results show that the inherent scatter among bond tests is large, even within groups of similar confinement and corrosion level. Nevertheless, the assessment model that has been developed can represent the degradation of anchorage capacity due to corrosion reasonably well. This new development of the model is shown to represent the experimental data better than the previous version; it yields similar results to an empirical model in the literature. In contrast to many empirical models, the model developed here represents physical behaviour and shows the full local bond stress-slip relationship. Using this assessment model will increase the ability of professional engineers to estimate the anchorage capacity of corroded concrete structures.

  • 10.
    Bok, Gunilla
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Brander, Linus
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Johansson, Pernilla
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Nya möjligheter att minska mängden deponerat gipsavfall från bygg- och ombyggnadsprojekt2018Report (Other academic)
    Abstract [en]

    Plasterboard is a common building material used in several parts of a building. In the case of retrofitting and demolition a part of the waste consists of components combined with the plasterboards, for example, frame work timber.

    In the case of new construction and retrofitting, construction waste is produced from clean plasterboard boards, either as cut off pieces or as unused whole boards. This waste can be used as raw material to produce new plasterboards. Manufacturers want to use gypsum from wasted boards to decrease the use of primary gypsum from mining and the quality requirements are relatively easy to achieve.

    In this project it has been found that the major construction companies already handle gypsum from new construction separately. This waste fraction could already be used in the production of new boards. Gypsum from retrofitting is usually assembled with other building materials and require more extensive efforts to achieve necessary purity to be used in the productions of new boards. Today, plasterboard waste is deposited or used to improve soil and/or sludge. In order to increase the recycling of plasterboards new inventory routines of rebuilding and demolition projects need to be elaborated. New tools and methods for dismantling plasterboard need to be development to achieve safe working environment and environmentally and economically sustainable recycling.

    Preparation plants producing raw material from plasterboard waste are already in operation. Today the waste mainly is wastage from the production stage. In order to increase the recycling of plasterboards from the construction- and demolition branch new logistic systems need to be developed, for example by creating collection points for gypsum board waste and / or developing new transport vehicles and systems. Prerequisites of changing the system of piece work in the construction industry need to be investigated with the intension to create a more sustainable building industry.

  • 11.
    Boubitsas, Dimitiros
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Tang, Luping
    Chalmers University of Technology, Sweden.
    Fridh, Katja
    Lund University, Sweden.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Utgenannt, Peter
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Frost Resistance of Concrete – Experience from Long-Term Field Exposure2018Report (Other academic)
    Abstract [en]

    This report presents the results from a research project financed by Trafikverket, the Swedish Transport Administration, co-financed by Cementa AB.

    The purpose of this project is to investigate concrete specimens exposed to a de-icing salt highway environment at Highway 40 close to Borås after about 20 years. The project work was divided into two parts: Part One for frost resistance of concrete and Part Two for chloride ingress and reinforcement corrosion.

    In Part One, more than 100 types of concrete mixes with different binder types/combinations, water-binder ratios (w/b) and air contents exposed at three field test sites were examined for external and internal frost damage by measurements of the changes in volume of, and in ultrasonic transmission time through, the specimens. Furthermore, some laboratory tests were carried out to supply necessary data for modelling and identify the possible mechanisms causing frost damage.

    The results show clearly that the highway environment is the most aggressive with regard to external frost damage. Further, the results from this study show that the existence of entrained air and the water-binder ratio are the main parameters influencing the resistance of concrete to external salt-frost damage. Furthermore, the concrete mixes with CEM I, CEM I + 5 % silica, CEM II/A-LL, CEM II/A-S and CEM I + 30 % slag as binder with entrained air and a water/binder ratio of 0.4 or below, has good resistance to internal and external frost damage. Results show that concrete containing large amounts of slag as part of the binder (CEM III/B) have the severest scaling, irrespective of its content of entrained air.

    Comparing results from laboratory testing of salt-frost resistance in accordance with SS 13 72 44 (the ‘Slab test’ in CEN/TS 12390-9) with results after nineteen years’ exposure at the highway exposure site shows that the laboratory standard classifies most concrete qualities correctly.

    However, there is an indication that the laboratory test method may overestimate the scaling resistance of concrete containing a medium to high content of slag as part of the binder. This indicates a need to consider a revision of the slab test procedure so that aging processes is better taken into consideration. A somewhat longer preconditioning time with at least partially an increased carbon dioxide content would for example lead to that the effect of carbonation is better reflected.

  • 12.
    Capener, Carl-Magnus
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Anna, Pettersson Skog
    Emilsson, Tobias
    Malmberg, Jonatan
    Jägerhök, Tove
    Edwards, Ylva
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Grönatakhandboken: Vägledning2017Report (Other academic)
  • 13.
    During, Otto
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Bhochhibhoya, Silu
    Univeristy of Twente, Netherlands.
    Kunar Maskey, Ramesh
    Kathmandu University, Nepal.
    Joshi, Rajendra
    Kathmandu University, Nepal.
    Rice Husk Resource for Energy and Cementitious Products with Low CO2 contributions2018In: Nordic Concrete Research, ISSN 0800-6377, Vol. 59, no 2, p. 45-58Article in journal (Other academic)
    Abstract [en]

    Rice Husk Ash (RHA) is a well-known supplementary cementitious materials (SCMs) that can be used for concrete with reduced CO

    2 contributions. In 2016, only Nepal produced 5.2 million tonnes rice that gave about 1.14 million tonnes rice husk. The rice husk can also be used directly in a cement kiln as a fuel. This study analysis the potential CO2 reductions from three scenarios and emphasis strengths, weaknesses, opportunities and treats in the production systems for initiate a decision process with possibilities to get an industry project financed from the green climate found. The highest CO2 benefits were from rice husk used in a cement kiln were half of the yearly rice husk production in Nepal could reduce the climate impact with 808000 tonnes CO2.

  • 14.
    Ekström, Daniel
    et al.
    WSP, Sweden.
    Al-Ayish, Nadia
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Simonsson, Peter
    Swedish Transport Administration, Sweden.
    Rempling, Rasmus
    Chalmers University of Technology, Sweden.
    Climate impact optimization in concrete bridge construction2017In: IABSE Conference, Vancouver 2017: Engineering the Future - Report, International Association for Bridge and Structural Engineering (IABSE) , 2017, p. 1161-1168Conference paper (Refereed)
    Abstract [en]

    Estimates indicate that the total climate impact, from a lifecycle perspective, generated by Swedish construction processes reaches the same magnitude as emissions from all passenger cars in Sweden. A large part of the emissions from construction of roads and railways arise from production of steel and concrete used in bridges and other infrastructure structures. In this research, several cases of existing concrete bridges have been investigated. The case studies are in a very firm way analyzed, and then opportunities for reducing climate gas emissions are described and elaborated upon. Accordingly, design and dimensioning through the use of today's technology and material selection are discussed. Without developing new ways to construct bridges, or comparing concrete with other materials, a useful guide on how to use technology and opportunities that are available for constructing climate smarter versions of standard bridges today is developed and described.

  • 15.
    Eriksson, Jonny
    et al.
    University of Gothenburg, Sweden.
    Lindqvist, Jan Erik
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Lime render, shrinkage cracks and craftsmanship in building restoration2019In: Journal of Cultural Heritage, ISSN 1296-2074, E-ISSN 1778-3674, Vol. 37, p. 73-81Article in journal (Refereed)
    Abstract [en]

    The present project concerns early shrinkage cracks in renders. This problem relates to the type of lime and rendering methods used in Sweden during the 19th and early 20th century as well as in current restoration practice. Results from different render restoration projects have indicated that a high frequency of shrinkage cracks could be related to the slaking procedure and the reworking of the slaked lime putty. The aim of the project was to investigate whether there is a connection between different handling procedures for wet-slaked lime putty and early shrinkage cracks in render. An investigation involving practical application and a laboratory test programme was initiated to examine the problem of early shrinkage cracks in renders based on wet-slaked sub-hydraulic lime. This type of lime was commonly used in Sweden in the 19th century. The laboratory work in the project included 3 different mix proportions based on reworked and non-reworked lime putty. The renders were applied after 1, 8, 15, 32 and 68 days storage of the lime putty. This gave 30 mortar mixes applied as rendered test surfaces. The flow number of the fresh mortars was determined and the workability, mixability and open time were assessed. The frequency of shrinkage cracks in the rendered surfaces was measured. The results showed that the frequency of shrinkage cracks was related to the methods applied in the slaking process and the storage time. Reworking and storage of the lime putty increased the frequency of shrinkage cracks. The properties of the fresh mortar were also influenced.

  • 16. Falchi, Laura
    et al.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Fontana, Patrick
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Balliana, Eleonora
    Izzo, Francesca
    Zendri, Elisabetta
    Artificial weathering of water-repellent mortars suitable for restoration applications2014In: Hydrophobe VII / [ed] Mimoso, J.-M., Charola, A.E., 2014Conference paper (Refereed)
  • 17.
    Flansbjer, Mathias
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Lindqvist, Jan Erik
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Meso Mechanical Study of Cracking Process in Concrete Subjected toTensile Loading2018In: Nordic Concrete Research, ISSN 0800-6377, Vol. 59, no 2, p. 13-29Article in journal (Other academic)
    Abstract [en]

    This project focused on how the cracking process in concrete is influenced by both the micro and meso structures of concrete. The aim was to increase knowledge pertaining to the effect of critical parameters on the cracking process and how this is related to the material's macroscopic properties. A methodology based on the combination of different experimental methods and measuring techniques at different scales was developed. Crack propagation during tensile loading of small-scale specimens in a tensile stage was monitored by means of Digital Image Correlation (DIC) and Acoustic Emission (AE). After testing, crack patterns were studied using fluorescence microscopy.

  • 18.
    Flansbjer, Mathias
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Lindqvist, Jan Erik
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Methodology for Mesomechanical Study of Concrete Material2017Conference paper (Refereed)
    Abstract [en]

    This project focuses on detailed studies of how the cracking process in concrete is influenced by the concrete micro- and mesostructure. The aim is to increase knowledge of how critical parameters affect the cracking process and how this is related to the material's macroscopic properties. A methodology based on the combination of different experimental methods and measuring techniques at different scale levels has been developed. Crack propagation during tensile loading of small-scale specimens in a tensile stage was monitored by means of Digital Image Correlation (DIC) and Acoustic Emission (AE). After the test, crack patterns were studied using fluorescence microscopy.

  • 19.
    Flansbjer, Mathias
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Williams Portal, Natalie
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Vennetti, Daniel
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Composite Behaviour of Textile Reinforced Reactive Powder Concrete Sandwich Façade Elements2018In: International Journal of Concrete Structures and Materials, ISSN 1976-0485, E-ISSN 2234-1315, Vol. 12, no 1, article id 71Article in journal (Refereed)
    Abstract [en]

    Within the EC funded project smart elements for sustainable building envelopes, carbon textile reinforcement was incorporated into reactive powder concrete, namely textile reinforced reactive powder concrete (TRRPC), to additionally improve the post-cracking behaviour of the cementitious matrix. This high-performance composite material was included as outer and inner façade panels in prefabricated and non-load bearing sandwich elements along with low density foamed concrete (FC) and glass fibre reinforced polymer continuous connecting devices. Experiments and finite element analysis (FEA) were applied to characterize the structural performance of the developed sandwich elements. The mechanical behaviour of the individual materials, components and large-scale elements were quantified. Four-point bending tests were performed on large-scale TRRPC-FC sandwich element beams to quantify the flexural capacity, level of composite action, resulting deformation, crack propagation and failure mechanisms. Optical measurements based on digital image correlation were taken simultaneously to enable a detailed analysis of the underlying composite action. The structural behaviour of the developed elements was found to be highly dependent on the stiffness and strength of the connectors to ensure composite action between the two TRRPC panels. As for the FEA, the applied modelling approach was found to accurately describe the stiffness of the sandwich elements at lower load levels, while describing the stiffness in a conservative manner after the occurrence of connector failure mechanisms. © 2018, The Author(s).

  • 20.
    Grigoriadis, K.
    et al.
    Queens University, UK.
    Whittaker, M.
    Queens University, UK.
    Soutsos, M.
    Queens University, UK.
    Sha, W.
    Queens University, UK.
    Napolano, L.
    STRESS S.C.AR.L, Italy.
    Klinge, A.
    ZRS Architekten Ingenieure GmbH, Germany.
    Paganoni, S.
    ZRS Architekten Ingenieure GmbH, Germany.
    Casado, M.
    ACCIONA Construction Technology Centre, Spain.
    Brander, Linus
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Rabade, Prieto
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mousavi, Marjan
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    During, Otto
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Scullin, M.
    CDE Global Ltd, Uk.
    Correia, R.
    CREAGH Concrete, uk.
    Zerbi, T.
    STAM S.R.L, iTALY.
    Merli, I.
    VORTEX HYDRA S.R.L, iTALY.
    Ingrosso, I.
    CETMA, Italy.
    Attanasio, A.
    CETMA, Italy.
    Largo, A.
    CETMA, Italy.
    Improving the recycling rate of the construction industry2019In: Sustainable Construction Materials and Technologies, International Committee of the SCMT conferences , 2019Conference paper (Refereed)
    Abstract [en]

    Construction and Demolition Waste (CDW) accounts for approximately 25-30% of all waste generated across Europe each year. However, Waste Framework Directive 2008/98/EC requires from all EU member states to achieve at least 70% re-use, recycling or other recovery of non-hazardous CDW by 2020. In response, the Horizon 2020 RE4 Project (REuse and REcycling of CDW materials and structures in energy efficient pREfabricated elements for building REfurbishment and construction) consortium was set up. Its main aims are to assess the quality of various CDW fractions (e.g. mineral aggregate, timber, plastics, silt & clay), improve the quality of mineral aggregates and develop different building elements/components which contain at least 65% of CDW. Innovative building concepts will also be developed in an effort to improve recycling rates of future buildings through the use of prefabrication and modular design. The developed products and technologies will be assessed in a number of test sites by building 2-storey demonstration houses.

  • 21.
    Gustafsson, Mats
    et al.
    VTI, Sweden.
    Kraft, Lars
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Olofsson, Ulf
    KTH Royal Institute of Technology, Sweden.
    Moderna betongbeläggningar: utveckling mot mindre slitage och partikelemission2019Report (Other academic)
    Abstract [en]

    Vägbeläggningar av betong har potential att vara ett intressant alternativ till asfalt på flera sätt. Betong är normalt sett slitstark och saknar fossila komponenter, vilket är gynnsamt ur klimatsynpunkt och för brandsäkerhet i t.ex. tunnlar. Betong är dock dyrare att lägga, vilket medför att ur ett hållbarhetsperspektiv måste betongen vara både slitstarkare och kräva mindre underhåll jämfört med asfaltsbeläggningar. Syftet med föreliggande projekt har varit att ta fram ett betongrecept (Betong 2), med bättre egenskaper avseende slitage och partikelemissioner jämfört med en känd standardbetong (Betong 1) och en slitstark asfaltsbeläggning (ABS16) baserade på samma ballastmaterial. Inledande försök på pinne-skiva-maskin visade att nötning och partikelkoncentration för vägmaterialen av betong uppvisar en omvänd proportionalitet mot ballastens hårdhet, och en direkt proportionalitet mot glidsträckan. I VTI:s provvägsmaskin jämfördes Betong 2 mot Betong 1 och mot en asfalt av typen ABS16. Provningen visade att slitaget var betydligt lägre för Betong 2 jämfört med referensasfalten (ABS16) och Betong 1. Genomgående genererar båda betongerna högre PM10-halter än asfalten. Ultrafina partiklar genereras i högre grad av asfalten. Orsaken till betongernas högre PM10-emission bedöms vara bidraget från cementpastan, vilket avspeglas i ett cirka tre gånger så högt kalciuminnehåll i PM10 från betongerna jämfört med PM10 från asfalten ABS16. Sammantaget visar både provningen i PVM och i detaljstudierna i pinne-skiva-maskin att Betong 2 har högre slitstyrka än både Betong 1 och asfalten ABS 16 och genererar generellt mindre PM10 än Betong 1.

  • 22.
    Hellman, Fredrik
    et al.
    VTI, Sweden.
    Eklöf, Ingemar
    Novus Ecsosystems, Sweden.
    Kraft, Lars
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Återvinning av däck i anläggningskonstruktioner: bättre resursutnyttjande av ett högvärdigt material2017Report (Other academic)
    Abstract [en]

    Gummi har särskilda egenskaper i förhållande till andra material. När uttjänta däck återvinns erhålls olika produkter som till stora delar har kvar sina gummiegenskaper. Det är till exempel mjukt, har isolerande och dränerande förmågor samt återfår sin ursprungliga form efter en belastning förutom att det är beständigt över tid. Dessa egenskaper kan utnyttjas för att framställa produkter och konstruktioner med unika kvaliteter, till exempel produkter som tål större deformation utan att gå sönder, som dämpar vibrationer och buller, som har en isolerande förmåga, har renande och stabiliserande förmågor. I anläggningsbranschen har man traditionellt mest utnyttjat antingen obundna granulära material, (sand och bergmaterial) eller bundna material (asfalt, betong). Gummimaterial i form av exempelvis granulat, däckklipp eller hela däck erbjuder möjligheter att utföra nya typer av anläggningskonstruktioner med speciella fördelar i förhållande till de traditionella konstruktionerna. Välkända exempel på hur man skapat en ny typ av konstruktioner baserat på gummits speciella egenskaper är konstgräsplaner med gummigranulat och fallskyddande lekplatsbeläggningar. Det finns stora potentialer att utveckla anläggningskonstruktioner med unika egenskaper där det återvunna materialet utgör eller till del ingår och som kommer bli efterfrågat för sin funktion och lönsamhet. Ett grundläggande problem, oavsett tillämpningar, är att det handlar om två olika värdekedjor och någon naturlig länk för att knyta samman dessa saknas. Den ena värdekedjan är utförande och anläggande av väg och anläggningskonstruktioner och den andra är återvinning av avfall och restprodukter. Dessa värdekedjor har traditionellt helt olika fokus på syfte och mål med verksamheterna varför det önskvärda förhållandet med både ”push and pull” inte naturligt uppstår. För att skapa denna länk måste någon part ta ansvar för det behov och den roll som uppstår i skärningspunkten mellan värdekedjorna. Vem som tar denna roll är den springande frågan för vidareförädling, tillverkning och utförande där återvunna däck helt eller till del utgör råvaran.

  • 23.
    Helsing, Elisabeth
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Salt-frostprovning av betong med slagg och flygaska2017Report (Other academic)
    Abstract [en]

    The purpose of the project has been to develop the salt-freeze-thaw method (the slab method in CEN TS/12390-9 and method A in SS 137244) further so that the results reflect what is taking place in the long run during real conditions in Swedish climate in concrete with binders containing slag and fly ash and thereby can be used to in initial tests in order to predict the salt-frost resistance of such concretes. By doing this basic knowledge about the salt-frost resistance of concretes containing slag a fly ash has been assembled.Since several studies have shown that the salt-frost resistance of slag concrete in particular is affected by carbonation, the influence of carbonation was studied. Concrete with slag and fly ash has a slower strength development at the early stages and the influence of this fact has also been included in the investigation.In the project 14 different concretes with varying binder compositions and the water-to-binder ratio 0.45 have been subjected to the standardized salt-frost scaling method and 5 variations of the method, where the age at sawing, the length of the conditioning period in 65 % RH and the carbon dioxide conditions have been varied. The tests have been accompanied by determination of strength development, air pore structure, weight gain during wetting and the first 28 frost cycles, inner degradation and analysis of the surface by XRD and microscopy. With some binder combinations mortar specimens have been prepared and on these sorption isotherms have been determined and TG-analysis and low temperature calorimetry tests have been carried out. Specimens for field exposure at the site adjacent to the main road 40 has also been prepared and placed. Within the project time only measurements after one winter season has been performed.The conclusion regarding the applicability of the existing test method is that for compositions with maximum 20 % slag or fly ash the method works well without adjustments. For compositions with higher amounts of slag or fly ash the conditioning should be completed with about one week exposure to 1 % CO2, in order to take into account the increased scaling due to carbonation. As regards the use on concretes with considerably slower strength development than normal the age of the specimens at the start of the salt-frost cycling can be increased to up to 90 days in order to reflect the performance in the long run. It should then also be ascertained that the concrete in question in a real case is not exposed to salt-frost attack at a lower maturity than what this represents.When it comes to the requirements on binder compositions for exposure class XF4, it is shown that the requirements which exist in SS 137003:2015 are fully adequate. Maximum 20 % slag or fly ash can be used without influencing the salt-frost resistance more than marginally at a water-to-binder ratio =0,45. Using 35 % fly ash or 65 % slag results in very large scaling. Using 35 % slag gives is ambiguous results, but may perhaps be acceptable if the maximum water-to-binder ratio in that case is decreased to 0,40.

  • 24.
    Helsing, Elisabeth
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Silva, Nelson
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Eva, Rodum
    Norwegian Public Roads Administration, Norway.
    Torkkeli, Minna
    Finnish Transport Agency, Finland.
    Hejll, Arvid
    Swedish Transport Administration, Sweden.
    A Nordic method for testing hydrophobic impregnations with regard to prevention of chloride ingress2017Report (Other academic)
    Abstract [en]

    Chloride induced corrosion of the reinforcement is the major cause of degradation of reinforced concrete structures. In particular in the Nordic countries, the use of de-icing salts during winter, leads to severe degradation of edge beams in road bridges. Thus, in order to extend the service life and decrease maintenance costs, hydrophobic impregnations are commonly used to prevent or slow down chloride ingress into concrete. There is a harmonised European standard for hydrophobic impregnations, EN 1504-2 [1], but the property “diffusion of chloride ions” is “subject to national standards and regulations”. The transport and road administrations of Sweden, Norway and Finland use different national methods to evaluate the performance of this type of products meaning that the same CEmarked product needs to meet different requirements. Therefore, the transport and road administrations of Sweden, Norway and Finland initiated a project with the aim to establish a common Nordic method for classification of hydrophobic impregnations with regard to their capability to protect concrete from chloride ingress. The project was divided into three phases consisting on the analysis of existing test standards (national and international), a pre-study to evaluate the influence of different tests parameters and a round robin test involving three laboratories (one in each country). A thorough comparison of the existing methods and review of relevant literature made it possible to define which test parameters could be used in the formulation of the new method and which ones required further studies. It was found that the type of surface to be treated, the length of the preconditioning period, the length of the curing period and whether the surface to be impregnated should be soaked with Ca(OH)2-solution or not should be further investigated. The results of the pre-study showed that the application of the impregnation to form surfaces led to somewhat better chloride blocking effect. Despite this, it was decided to use sawn surfaces in the method, since it is much easier to obtain reproducible surface characteristics that way. The characteristics of a form surface depend on e.g. the form material, use of release agents, curing conditions. Saturation of the surface with calcium hydroxide solution before impregnation was found slightly beneficial on the chloride blocking effect compared to when such a treatment was omitted. However, since this did not contribute to the robustness of the test results, it increased the number of experimental steps and it is not representative of practice in real structures, it was decided not to incorporate such a treatment in the new method. The chloride protection slightly increases with the impregnation curing time. It was not clear which factor was most dominant; if the continuous polymerization of the hydrophobic impregnation or the continuous cement hydration. Since enough curing time is necessary for the treatment to be efficient, it was decided that the curing period before exposure to chlorides should be 28 days. With the primary objective of determining the reliability and reproducibility of the new method, a round robin exercise was carried out. Three laboratories were involved in this phase; CBI-Borås in Sweden, SINTEF in Norway and VTT in Finland. The results show that despite some differences in both materials and methods, such as the type of cement or preconditioning and curing environments, highly reproducible results were obtained. In addition, a detailed discussion on the influence of the details of the method on the chloride profiles and on the filter effect is presented. Within the round robin test, the relative humidity before and after impregnation and the dry condition of the powder samples were found to be the major parameters leading to the discrepancy of the results. In addition, handling of the wet concrete surfaces after exposure to chlorides and the time period (and temperature) between the end of the chloride exposure and powder sampling for chloride analysis were found to have surprisingly large effects on the form of the chloride profiles in the samples. Therefore, these parts of the procedures were made much more precise in the final method, in order to increase its reproducibility. The method can be briefly described as follows: Concrete specimens are prepared by sawing 100 mm cubes into two halves, three cubes per test series. The sawn surfaces are defined as exposure faces. Three halves are treated with the hydrophobic impregnation to be tested and the other three halves are kept as untreated references. The specimens are exposed submerged in 15% NaCl-solution for 56 days. After exposure, the chloride ingress is determined by profile grinding and the total amount of penetrated chlorides is calculated. The chloride blocking effect of the hydrophobic impregnations, expressed as the Filter Effect, FE, which is determined as 1 minus the ratio between the amount of penetrated chlorides in treated and in non-treated concrete specimens. The results obtained in both the pre-study and round robin exercise were compared to those obtained with the existing national methods in order to establish proper requirement levels with the new method. Despite the many differences between the methods, it was found that a filter effect of approximately 0.65 correlates well with the existing requirement in the Swedish method and in the Norwegian method. However, given limited data available and also considering data from field investigations, a level of 0.60 is proposed as appropriate for a really well performing hydrophobic impregnation. The method was accepted as a Nordtest method in December 2015 with the denomination NT Build 515.

  • 25.
    Helsing, Elisabeth
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Parg, Lisa
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Ellison, Tommy
    BESAB, Sweden.
    Hydrofoberande medel i sprutbetong: Inverkan på egenskaper och beteendet vid sprutning2017Report (Other academic)
    Abstract [en]

    The overall goal with this project is to acquire more profound knowledge and experiences as regards the use of hydrophobic agents added to fresh concrete (hydrophobic admixtures) intended for sprayed concrete with low-alkali binders, with the purpose to enhance the durability and serviceability of the sprayed concrete. The results from this project contribute to increased understanding of the practical possibilities with and limitations for hydrophobic admixtures in sprayed concrete. Thus the need for costly field tests, with trial and error can be decreased.A large part of the project has been devoted to study the influence of the hydrophobic admixtures on the properties at an early stage, since these are decisive for the practical application. In addition the influence on strength development and bond have been determined. The hydrophobicity that these admixtures give the concrete has also been investigated. These tests have primarily been carried out on paste, mortar or concrete cast in a traditional way, not on sprayed concrete. Spraying tests have been carried out with one of the hydrophobic admixtures and a reference without admixture in order to study the behaviour at spraying. On samples from the sprayed concrete the bond, hydrophobicity and chloride intrusion have been determined.Two hydrophobic admixtures, Sitren P 750 (E) and Silres BS 1001 (W) have been used, both based on organosilicates. Admixture E consist of a modified siloxan which is attached to silica fume and admixture W is a water based emulsion of silan/siloxan. Most of the tests were carried out on a pure Portland cement (Degerhamns Anläggningscement from Cementa) and on a Portland-fly ash cement (Slite Anläggning FA from Cementa). Both cements are sulphate resistant and have low alkali content. Tests with and without accelerator have been carried out.When used without accelerator admixture W influenced the setting time and the heat development much more than admixture E. Admixture W had a clear retarding effect. It was though possible to compensate for this effect by adding an accelerator. The 28 day strength decreased when both admixtures were used, most with admixture W. But also in this case this effect was to some extent compensated by adding an accelerator. The accelerator did not have a decisive influence when admixture E was used. When the bond was determined on cast concrete admixture W gave higher and less deviating results than admixture E. The hydrophobicity in mixtures with the two admixtures was comparable.The spray test was carried out with admixture W and an accelerator. With the admixture less water was needed to give the same workability. The behaviour at spraying was as good as, or somewhat better, with the hydrophobic admixture compared to the mix without. The hydrophobic admixture did not influence the bond of the sprayed concrete. The water absorption of the sprayed concrete with the hydrophobic admixture was approximately 30 % lower than without, and the resistance to chloride intrusion was approximately 40 % higher.

  • 26.
    Hesselgren, Lars
    et al.
    PLP Architecture, Sweden.
    Andreasson, Ingemar
    LogistikCentrum, Sweden.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Prieto Rábade, Miguel
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Janhäll, Sara
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    NuMo – New Urban Mobility: New urban infrastructure support for autonomous vehicles2019Report (Other academic)
    Abstract [en]

    Foreword All transport systems have a certain capacity determined by its configurations. For cars the most efficient current form is constant speed driving, e.g. the motorway. Its capacity is limited by the time separation between vehicles. Any transport system that stops because of congestion or other causes by definition sees its capacity reduced to zero. Hence traffic jams are hugely disruptive. Public transport operates on a model inherited from the 19 th Century. Vehicles (buses, trams, railways, metros) run on a regular (timetabled) basis and stops at every station (bus stop). Since there is no pre-booking and the need of transport is hard to foresee, the vehicles are often almost empty, at other times hugely congested. The NuMo technology emerges from decades of work across the whole transportation industry. Autonomous electric vehicles (AEVs) equipped with vehicle-to-vehicle (V2V) communication can safely keep shorter distances. In practical terms this means that a platooned car system has the same capacity in one lane as a double-lane motorway. Automated intelligent controls ensure that the NuMo systems never stops, thus achieving the highest capacity. Instead of waiting for the mass deployment of fully automated vehicles, NuMo starts with dedicated networks that integrate tightly with existing infrastructure for step-wise smooth transition to fully automated transport system. NuMo includes an on-demand public transport system which only runs when it is needed. The system will take advantage of close-spacing possible with robot controls – vehicles can run close together and also use less road width by less wiggling. Equally importantly stations and access to the normal road network is arranged such that the traffic flow never stops. The urban impact can be imagined by understanding the impact of modern public transport systems currently under construction. Some of them are underground to avoid disrupting the street patterns. Some are elevated, some rely on physical separation at grade. One interesting option is to use tunnels underground or in water to further reduce disruption. Many cities are abandoning the traditional port infrastructure giving huge opportunities to again regard water as a connector rather than something to cross. The NuMo system uses all of those techniques and detailed design studies are under way for each of those options. NuMo will make an important contribution to environmental sustainability in many respects. Firstly, it will accelerate adoption of electric propulsion; secondly it will encourage vehicle sharing; and thirdly by only running when needed will save on unnecessary movements and finally its construction costs will be less than conventional systems. Sketches of NuMo networks are presented on places as diverse as Stockholm, Gothenburg and New York. Naturally the system will also be crucial in the development of new cities. This report is a summary of the studies performed within the project “New urban infrastructure support for autonomous vehicles” financed by Vinnova through the Strategic Innovation Program InfraSweden2030. The aim is to explore the infrastructure support to accelerate the introduction of autonomous electric vehicles for future mobility.

  • 27.
    Jacobsson, Lars
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Appelquist, Karin
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Lindqvist, Jan Erik
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Åkesson, Urban
    Swedish Transport Administration, Sweden.
    Spalling initiation experimentson large hard rock cores2018Report (Refereed)
    Abstract [en]

    A new type of laboratory test method to determine spalling resistance in a situation as in large boreholes in hard rock has been demonstrated. Uniaxial compression tests on large cores with notches were conducted on Äspö diorite from Äspö HRL. Spalling was localized to the notches where the local stress was highest. The crack initiation, crack coalescence and crack damage stresses representing various fracture stages were identified by using acoustic emission monitoring with source localization. The actual stress levels were obtained from the axial forces at which the various fracture stages were identified via FE-calculations representing the actual specimen geometry and loading. The results were compared with uniaxial compression tests carried out on cores with standard size on the same rock type also from Äspö HRL.

    The results showed that spalling chips were formed similar to those found in field which indicates that the test is representing a realistic behaviour. However, the results show that the various fracture stress levels found in the tests are higher than the spalling strength found in the field and in the test of small cores. The higher stress levels could be caused by a number of reasons described in the report.

    A post characterization of the fractures was carried out on slabs that were cut out from the specimens containing the notch areas. The occurrence of microcracks and how they have propagated through the different minerals and the location in relation to the notches, minerals and grain boundaries were investigated. The patterns of the major fractures and the secondary fractures were analysed. The majority seem to be extension fractures, but shearing could also be verified. The results from the microscopy analysis provide invaluable information of the spalling process at all stages.

  • 28.
    Jacobsson, Lars
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Lindqvist, Jan Erik
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Laboratory investigation of crack initiation on hourglass-shaped granite specimens2018In: Geomechanics and Geodynamics of Rock Masses, Volume 1: Proceedings of the 2018 European Rock Mechanics Symposuim / [ed] Vladimir Litvinenko, London: CRC Press, 2018, p. 633-638Conference paper (Refereed)
    Abstract [en]

    Laboratory experiments on axially compressed hourglass-shaped specimens of medium to coarse grained granite specimens were conducted. A tangential stress is generated in the circular notches which is intended to initiate surface spalling similar to what can be seen at circular openings in a rock mass. Specimens of three different sizes were tested with notch radii 98.4, 225 and 375 mm, which are equivalent to a hole diameter of 197, 450 and 750 mm. The spalling initiation and progress in the notches were monitored by acoustic emission and digital correlation measurements. From the acoustic emission measurements it could be seen that the tangential stress at spalling initiation decreased with increasing notch radius. Results from digital image correlation show how the surfaces in local zones in the notch were pushed outwards due to subsurface cracking parallel to the notch surface. Analyses of thin sections and polished slabs taken in the notch area showed that the cracking depth increased with increasing notch radius.

  • 29.
    Jacobsson, Lars
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Lindqvist, Jan Erik
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Laboratory investigation of stress gradient effect at spalling experiments on granite2015In: The 13th International Congress of Rock Mechanics: ISRM Congress 2015, 2015Conference paper (Refereed)
    Abstract [en]

    A series of laboratory tests were conducted to study stress-induced spalling on medium to coarse-grained granite specimens. The specimens made from cylinders had two manufactured notches on opposite sides aimed to represent the tangential loading around a circular opening. Specimens of three different sizes were tested with notch radii, 98.5, 225 and 375 mm, representing 197, 450 and 750 mm diameter holes, to study the effect of notch radius on the spalling initiation stress. The cracking was monitored by acoustic emission sampling. The fracture patterns were investigated visually on polished slabs and by microscopy on thin sections. The crack analysis describes how the cracks propagate in relation to the grain structure in the rock and to the macroscopic stress field.

  • 30.
    Jacobsson, Lars
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Sandström, Johan
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Brander, Linus
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Wedge splitting tests on granite and gneiss specimens2018Conference paper (Refereed)
    Abstract [en]

    The conditions for initial tensile cracking around a rounded blunt and a sharp notch and subsequent propagation were investigated by means of wedge splitting tests on structurally isotropic granite. In addition, the crack initiation and propagation on anisotropic gneiss specimens with a blunt notch were investigated in two different material directions. The wedge splitting test specimens which has a straight notch is normally used to determine mode I fracture properties for concrete but not for rock materials. The use of a straight notch in the specimens instead of a chevron type of notch, which is commonly used for fracture mechanics tests, was found to be well suited for the actual type of investigation. 

    The development of fractures from the notch into the specimens was monitored by measuring the deformation field on the specimen surface by digital image correlation (DIC) and by the crack mouth opening displacement. The fracture patterns were different in the granite and the gneiss. The DIC illustratively showed how cracks branched along the main crack path in the granite whereas no branching occurred in the gneiss material. This could also be verified by studying thin sections taken along the fracture path. It was seen that the granite behaved more ductile than the gneiss. 

    A finite element model of the wedge splitting test was made where the crack propagation was modelled using a cohesive-zone model and calibrated using the results from the experiments. The fracture energies were computed and it was found that the energies were about 50-100 percent higher in the granite than in the gneiss. The tensile stress cracking initiation in granite for the blunt and the sharp notch was slightly different. The gneiss specimens were all with a blunt notch and a comparison of the two notch types could not be made in this case.

  • 31.
    Jacobsson, Mikael
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Betongskador i vattenverk2016Report (Other academic)
    Abstract [sv]

    Rapporten ger en översikt över betongskador i svenska vattenverk. Den presenterar bilder på typiska betongskador, hur de kan uppstå och var man kan hitta dem i vattenreningsprocessen. Den ska inspirera vattenverkens personal att lägga märke till betongskador i tid. Detta för att undvika mycket genomgripande reparationer av allvarligare skador i framtiden. Betong är det i särklass vanligaste materialet i svenska vattenverk. Det är mycket hållfast, men det finns det flera kemiska och fysikaliska processer som påverkar materialet negativt. Nedbrytningen av betongen kan ses på bassängernas sidor, både våta och torra. Men det är inte helt ovanligt att skador uppstår även inuti en betongkonstruktion utan att det syns på utsidan. Oavsett var skadorna börjar kan tillsynes obetydliga betongskador göra att konstruktionens bärighet försämras avsevärt. De flesta vattenverk lider av likartade betongskador. Yterosion och urlakning av betongytan är de vanligaste formerna av synliga betongskador på den våta sidan. På den torra sidan är det vanligare med armeringskorrosion, sprickbildning och läckage. De skador som är vanligast inuti en betongkonstruktion är expansion, korrosion och svartrost. Svartrost bildas när armeringsjärn korroderar under syrefattiga förhållanden. Den expanderar inte på samma sätt som annan rost utan kan fylla ut håligheter i betongen utan att det syns på ytan. De inre skadorna är särskilt allvarliga eftersom det kan vara svårt att observera dem utan att det görs en utförlig tillståndsbedömning. Inre skador kan på sikt göra att hela konstruktionens bärighet går förlorad. Därför är det viktigt att regelbundet låta undersöka betongkonstruktionerna. Projektet genomfördes av CBI Betonginstitutet, som utför åtskilliga tillståndsbedömningar på betongkonstruktioner i Sverige varje år. I många fall visar det sig att konstruktionerna är i relativt dåligt skick. Troligen beror det på att de flesta skador utvecklas mycket långsamt och gradvis. Dessutom är vattenverkspersonalen inte alltid medveten om hur betongskador kan se ut eller hur allvarliga de kan vara. Om medvetenheten hos personalen höjdes skulle troligen många betongskador upptäckas tidigare och reparationer skulle kunna sättas in innan skadorna har blivit allvarliga och kostsamma att åtgärda. Även om en skada upptäcks behöver den inte alltid repareras direkt. I stället bör man om man hittar en skada låta en betongexpert utföra en tillståndsbedömning på konstruktionen. Det innebär att man undersöker omfattningen av konstruktionens skador, om de behöver repareras omedelbart eller senare, vilken form av reparation som bör utföras och med vilka material. Man kan också få rekommendationer om hur den reparerade konstruktionen kan skyddas i fortsättningen. Om en reparation inte behöver utföras direkt bör i stället konstruktionen övervakas med vissa tidsintervall.

  • 32.
    Jena, Naresh K.
    et al.
    KTH Royal Institute of Technology, Sweden.
    Lyne, Åsa L.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Arul Murugan, N. Arul
    KTH Royal Institute of Technology, Sweden.
    Ågren, Hans
    KTH Royal Institute of Technology, Sweden.
    Birgisson, Björn
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Texas A&M University, USA.
    Atomic level simulations of the interaction of asphaltene with quartz surfaces: role of chemical modifications and aqueous environment2017In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 50, no 1, article id 99Article in journal (Refereed)
    Abstract [en]

    Understanding the properties of bitumen and its interaction with mineral aggregates is crucial for future strategies to improve roads and highways. Knowledge of basic molecular and electronic structures of bitumen, one out of the two main components of asphalt, poses a major step towards achieving such a goal. In the present work we employ atomistic simulation techniques to study the interaction of asphaltenes, a major constituent of bitumen, with quartz surfaces. As an effective means to tune adhesion or cohesion properties of asphaltenes and mineral surfaces, we propose chemical modification of the pristine asphaltene structure. By the choice of substituent and site of substitution we find that adhesion between the asphaltene molecule and the quartz surface can easily be improved at the same time as the cohesive interaction between the asphaltene units is reduced, while other substituents may lead to the opposite effect. We also provide insight at the molecular level into how water molecules affect interactions between asphaltenes and quartz. Our approach emphasizes a future role for advanced atomistic modeling to understand the properties of bitumen and suggest further improvements.

  • 33.
    Johansson, Pernilla
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Brander, Linus
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Jansson, Anna
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Karlsson, Stefan
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Landel, Pierre
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Svennberg, Kaisa
    Kvalitet hos byggnadsmaterial i cirkulära flöden2017Report (Other academic)
    Abstract [en]

    The aim of the project presented in the report was that construction and demolition waste will be recycled or recycled to a greater extent and at the same time fulfil the quality requirements on the materials.

    The purpose of the project has been to map and compile the knowledge and experience of the technical aspects of circular flows of building materials, focusing on quality issues, identifying new projects that can reduce the amount of construction and demolition waste deposited or burned, as well as creating new networks. There is widespread knowledge in the construction industry about these issues and there are also a wide range of research results in different areas. In the project, knowledge and experience have been gathered through literature studies, workshops and seminars, study visits and interviews.

    The first part of the report discusses general technical experiences and challenges in different parts of the building chain, while challenges for specific material groups are discussed in the second part of the report. These material groups are polymeric materials, flat glass, stone wool, glass wool, plasterboard, crushed concrete, wood and wood-based materials. The report also presents a survey conducted by Optimera among their professional costumers, which aimed at collecting their experiences and views on sustainable construction.

    In general, we can find that there are major challenges in increasing recycling rates for demolition and refurbishment waste. For installation and construction waste, the technical challenges are not as big. Challenges and conditions for increased recycling and reuse with retained good quality vary between different types of materials / products, type of construction project and intended use.

    The report proposes a number of proposals in areas where work can be continued. These include improved / expanded inventory for demolition and refurbishment, routines and sampling methods, proper sorting, handling and storage to ensure the right quality, to provide the ability to separate compound materials, logistics, production technology and quality assurance. The results also show the importance of education, networks and meeting places and that research projects are conducted interdisciplinary. There are good opportunities for increased recycling through cooperation throughout the entire building chain.

  • 34.
    Jones, Frida
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Johansson, Inge
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Dahl, Jonas
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Todorovic Olsson, Jelena
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    Sahlin, Eskil
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Brander, Linus
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Förekomstformer av bly, koppar och zink i askor från avfallsförbränningsanläggningar2018Report (Other academic)
    Abstract [sv]

    Under 2014 reviderades den europeiska lagstiftningen avseende klassning av farligt avfall vilket också påverkar klassificeringen av askor från avfallsförbränning, framförallt bottenaskor. Den klassningsmetodik som främst används för askor i Sverige idag har behov av stöd för att motivera valen av referenssubstanser. Detta föranledde föreliggande projekt med syftet att göra en genomgång av förekomstformer för bly, koppar och zink i flygaskor och bottenaskor, som rapporterats i vetenskaplig litteratur. Till detta kommer också en diskussion om lakning baserad på ett antal rapporter valda i samråd med referensgruppen till projektet.

    Litteraturstudien har undersökt ca 150 publikationer totalt. Genomgången visar att det för bottenaskor finns väldigt lite publicerat kring förekomstformer av bly, koppar och zink. För flygaskor finns det däremot fler publikationer. De artiklar och rapporter som har identifierats visar stor spridning av olika förekomstformer. Dock är det sällan många forskare/forskargrupper som hittat samma mineral/kemiska föreningar. Om detta beror på skillnad mellan vilka föreningar man letat efter (vilket är en begränsning i analysmetoderna) eller om det beror på skillnader i askans sammansättning är svårt att svara på. Det finns heller ingen enighet om hur de resultat som finns rapporteras; detta gäller både för val/användande av analysmetod och på vilken bas koncentrationer rapporteras. Nästan varje ny, för projektet relevant referens, rapporterar om en eller flera mineralformer som inte fanns i tidigare referenser. Detta har gjort att antalet förekomstformer rapporterade i denna litteraturstudie är relativt stort men att det oftast är en eller ett par olika askor som de rapporteras för. Även detaljnivån på bakgrundsdata som från vilket bränsle eller panntyp som askorna härstammar skiljer sig mycket åt mellan publikationerna. Det gör det svårt att bedöma relevansen av resultaten i de olika publikationerna. De kvantifierade förekomster som finns är nästan helt uteslutande framtagna på olika typer av flygaskor.

    Vid en jämförelse mellan resultaten av projektet och de referenssubstanser som används i den tidigare nämnda beräkningsmodellen rekommenderar projektet:

    • Ett tillägg av metalliskt bly som referenssubstans för blyföreningar

    • att koppar(II)oxid byts mot koppar(II)hydroxid för flygaska (kvarstår som koppar(II)oxid för bottenaska)

    • att zink(II)oxid byts mot zink(II)klorid för flygaskor (kvarstår som zink (II)oxid för bottenaskor)

    Däremot anser projektet inte att det finns tillräckligt underlag för att rekommendera en generell fördelning mellan referenssubstanserna.

    Projektet visar alltså att det finns relativt lite material i litteraturen kring förekomstformerna i aska. För att öka kunskapen inom området och komma framåt avseende klassificeringsfrågan finns det olika vägar att gå. Generellt är det ett väldigt komplext område och rekommendationen är att gå vidare med en kombination av lakningsstudier, beräkningsmetoder och analyser av förekomstformer med specialiserade tekniker, som till exempel kan göras vid Max IV i Lund.

  • 35.
    Karlsson, Stefan
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Kalinowski, Mariusz
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Lang, Maria
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Sehati, Parisa
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Järphag, Thomas
    NCC Building, Sweden.
    Storm, Oskar
    Saint-Gobain Building Glass Polska, Poland.
    Axelsson Thun, Anders
    Skanska Sverige, Sweden.
    Häll, Jörgen
    Glascentrum, Sweden.
    Korrosion av planglas inom byggbranschen kopplat till betong2019Report (Other academic)
    Abstract [sv]

    Ett förekommande problem under byggprocessen är betongrinning. Innebörden av betongrinning är att vatten varit i kontakt med färsk betong och därefter påverkat glasytor till fasader/balkonger/fönster. Påverkan på glaset kan vara fysisk och ibland även kemisk. Resultatet blir droppfläckar, rinnmärken och utfällningar som försämrar glasets ljusgenomsläpplighet och estetiska intryck. Så länge påverkan enbart är fysisk är denna skada relativt lätt att ta bort antingen med hjälp av mekanisk polering eller genom att torka glaset med utspädd syra. Ofta fortskrider dock processen till ett kemiskt angrepp på glaset, vilket är permanent och inte går att avlägsna helt med ovan nämnda metoder. Kemiska reaktioner har då skapat etsningar i glasytan som på sikt blir i storleksordningen mikrometer djupa.

    I denna förstudie har vi försökt simulera betongrinningsangrepp dels under kontrollerade förhållanden i laboratoriemiljö och dels i utomhusmiljö. Försöksvariablerna var två olika betongvarianter samt glas med respektive utan ett på marknaden befintligt glasskyddande medel. Resultatet av försöken har analyserats genom okulär bedömning, mikroanalys med svepelektronmikroskop och energidispersiv röntgenspektroskopi samt yttopografimätningar med optisk profilometer. Testerna resulterade i utfällningar på glasytan innehållande ämnena svavel, kalium och kalcium, vilka bedöms härstamma från betongen. Efter inomhusförsöken, som pågick i fyra månader, gick utfällningarna att tvätta bort med saltsyralösning, och inga djupgående, permanenta korrosionsskador syntes på glaset. Utomhusförsöken utsträcktes till elva månader, varpå bestående skador kunde konstateras på glasytorna efter att utfällningarna tvättats bort. Djupet på skadorna uppmättes som mest till cirka en halv mikrometer. Varken sänkning av pH i betongen eller skyddsbehandling av glaset bidrog till att hindra uppkomst av fläckighet eller etsningar på glaset. I diskussioner med industrirepresentanter konstaterades att betongrinning är ett ganska vanligt problem, som är oberoende av geografi. Tidigare försök med behandling av både betong och glas varit verkningslösa. I majoriteten av fall handlar problemen om inglasade balkonger alternativt glasräcken i kombination med balkongplatta i betong. Det man vet fungerar är att använda en korrekt konstruktion som hindrar vattnet från att droppa ned på glaset. Regelbunden rengöring av glasen hjälper också och kommer förmodligen hamna som ett underhållskrav mot kunder.

  • 36.
    Kraft, Lars
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Eriksson Brändels, Alexander
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    McCarthy, Richard
    RISE - Research Institutes of Sweden, Certification, Certification.
    Litteraturstudie - Ökad användning av SKB för minskning av arbetsskador från vibrationer2019Report (Other academic)
    Abstract [en]

    Thepurpose of this study is to highlight the possibility of a better workingenvironment through an increased use of Self-Compacting Concrete (SCC). Suchconcrete is denser and more durable, has higher compressive strength and abetter filling capacity. The main advantage of SCC is that it doesn’t requirevibration for proper compaction and therefore is better to work with. Despiteinitial higher cost to order, it becomes cheaper in a life cycle analysis. Ofall industries, the construction industry has the highest number of workersaffected by vibrations. According to statistics 2016, vibration damage totaled 36% of all approved occupational diseases. The resulting damage can rarely becured and often leads to reduced working capacity and to severe life-longproblems. A study showed that exposure increase of vibrations of just 1 m/s2increases the risk of white fingers (9%), Raynaud’s phenomenon (6.9%),neurosensory injury (7.4%) and carpal tunnel syndrome (2.9%). Most of thevarious activities with elements of vibration on the construction site, such assawing, grinding, screwing with machine etc., are difficult to replace withvibration-free methods. But for concrete casting, it is now possible to almostcompletely exclude vibrations by using SCC. The increased knowledge of theimportance of a healthy workplace for the economic performance of constructioncompanies has played a key role for work environment work. One study comparedthe benefits of accident prevention initiatives with the costs of the same. Itwas revealed that the benefit surpasses the costs with the relationship 3:1. Improvementsfor a healthier workplace can be achieved by: New innovations, both mechanicaland material innovations, making work easier. Studies using modern portablesensors from which information can play an important role in the possibility ofreducing work-related musculoskeletal disorders.

    Encouragingworkers to use wearable sensors that can alert when ergonomically dangerousmovements are carried out. Changing of an often reluctant culture at theworkplace. Better risk assessment at the design stage. Better planning inproject design in the early stages using new digital tools such as BIM. Betterinformation about risks and safety in order to affect the safety behaviour ofworkers. We recommend a larger working environment study that will show how apositive workplace development with SCC is possible and how much can be savedin this way. Here, medical expertise must be involved to increase reliability.In addition, there is a desire in medical research, on the working environmentand on vibration-related injuries, to fill in the gaps in previous researchthat remain, such as how cold weather and individual risk factors, such assmoking, affect the risk of vibration-related work injuries.  Improved working environment is the mainreason for increased use of SCC. Increased use should provide a moresustainable society.

  • 37.
    Kurkinen, Eva-Lotta
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Al-Ayish, Nadia
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Brick, Karolina
    Riksbyggen, Sweden.
    Rönneblad, Anders
    Cementa, Sweden.
    Brunklaus, Birgit
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    During, Otto
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Larsson, Oskar
    Lund University, Sweden.
    Kriterier för resurssnålt byggande i praktiken: Slutrapport från forskningsprogrammet E2B2 – energieffektivtbyggande och boende2018Report (Other academic)
    Abstract [sv]

    Arbetet omfattar uppföljning av ställda kriterier för låg klimatpåverkan från betong vid upphandlingav betongstomme för brf. Viva i Göteborg. Kriterierna följdes upp dels genom att LCA studien somgenomförts under programskedet uppdaterades med data för den färdigupphandlade byggnaden ochdels genom att interljuva ett urval av aktörer för att få en inblick över hur branschen ser på de ställdakraven. Arbetet innehåller även en avslutande del angående känsligheten i beräkningarna samtosäkerheter och hur de kan behandlas.Byggnaderna som är tänkta att stå i 100 år kommer utsättas för klimatförändringar. Därförgenomfördes parallellt med LCA studien också energisimuleringar för att se hur den termiskakomforten och uppvärmningsbehovet förändras över tiden.Resultaten av LCA-uppföljningen och de ställda kriterierna visar att kraven uppfylldes för både denprefabricerade betongen och den platsgjutna betongen. Att jämföra den totala klimatpåverkan mellanprogramskedet och upphandlad byggnad visar sig inte vara möjligt då konstruktionen har förändratsalltför mycket, bland annat har den uppvärmda ytan ökat med ca 50% samtidigt som mer material haranvänts för de prefabricerade väggarna och bjälklagen. En känslighetsanalys har istället genomförtssom visar att den upphandlade konstruktionen har 30% lägre klimatpåverkan per BOA jämfört motom den byggts med traditionell betong. Hade de ursprungliga konstruktionsdetaljerna frånprogramskedet använts för väggar och bjälklag hade klimatpåverkan istället varit ca 40% lägre.Vid framtida kravställning bör man därför ta hänsyn även till konstruktionerna, betongkvaliteternaoch dess materialmängder och inte bara ställa krav på betongrecepten som i det här fallet.Klimatsimuleringarna visar att det troligen finns ett stort mörkertal med lågenergilägenheter som harförhöjd temperatur inomhus sommartid redan vid dagens klimat

  • 38.
    Kurkinen, Eva-Lotta
    et al.
    RISE - Research Institutes of Sweden, Built Environment, Building Technology.
    Al-ayish, Nadia
    Brick, Karolina
    Riksbyggen, Sweden.
    Rönneblad, Anders
    Cementa, Sweden.
    Brunklaus, Birgit
    RISE - Research Institutes of Sweden, Built Environment, Energy and Circular Economy.
    During, Otto
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Larsson, Oskar
    Lund University, Sweden.
    Resurssnålt byggande: så ställs kraven för minstamöjliga klimatpåverkan: Resultatblad från forskningsprogrammet E2B2 –energieffektivt byggande och boende2018In: Energimyndigheten E2B2Article, book review (Other (popular science, discussion, etc.))
  • 39.
    Lindgård, Jan
    et al.
    SINTEF, Norway.
    Grelk, Bent
    NTNU Norwegian University of Science and Technology, Norway.
    Wigum, Børge Johannes
    NTNU Norwegian University of Science and Technology, Norway.
    Trägårdh, Jan
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Appelquist, Karin
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Holt, Erika E.
    VTT, Finland.
    Ferreira, Miguel
    RILEM, Finland.
    Leivo, Markku
    VTT, Finland.
    Nordic Europe2017In: Alkali-aggregate reaction in concrete: a world review / [ed] Ian Sims, Alan B. Poole, Taylor & Francis, 2017, p. 277-320Chapter in book (Other academic)
  • 40.
    Lindström, Camilla
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Appelquist, Karin
    Ramboll, Sweden.
    Brander, Linus
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Sjöqvist, Lovise
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Kvantifiering av mikrostrukturer och dess inverkan på sprickbildning i berg2019Report (Other academic)
    Abstract [en]

    A new methodology based on monitoring of crack propagation during small-scale mechanical tests on sawn rock prisms under tension has been developed. The methodology includes a combination of different experimental methods and measuring techniques at different scale levels. Material testing is performed through a tensile stage. Crack monitoring is performed by means of Digital Image Correlation and Acoustic Emission. After the test, microcrack and fracture patterns are studied and quantified in thin-sections using fluorescent light under a petrographic microscope.

    By using Digital Image Correlation it is possible to follow crack propagation in relation to the microstructure on the surface of the specimen in a detailed way, whereas Acoustic Emission offers real-time measurement of the crack activity within the specimen. By combining these techniques, it is possible to relate the Acoustic Emission signal characteristics to different phases of the cracking process, such as crack initiation, propagation and bridging of microcracks into macrocracks as well as the creation and localization of the final fracture. After the tensile stage test, crack patterns and the final fractures are studied in detail using polarizing and fluorescence microscopy, establishing the relationship of these. The methodology is practiced to increase the knowledge of critical parameters affecting cracking processes in rock materials and to show how this is related to the material's microstructure as well as mesostructure.

  • 41.
    Lundgren, Monica
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Babaahmadi, Arezou
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Exposure experiments in sulfate containing solution, including exposure at low temperature2018Report (Other academic)
    Abstract [en]

    This report describes results of an investigation on the sulfate resistance of dual blended binder of mortar and concrete specimens over a period of 1 year. The focus is on showing the importance of the chemistry of the components when discussing sulfate resistance and the relation of that to the hydrate phase assemblage. Moreover the importance of the test method for evaluations is pointed out.

  • 42.
    Lundgren, Monica
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Helsing, Elisabeth
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Babaahmadi, Arezou
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    State-of-the-Art Report on: Material Type, Requirements and Durability aspects of Sprayed Concrete in Tunnels2018Report (Other academic)
    Abstract [en]

    The report summarizes a state-of-the-art for sprayed concrete applied for ground support in tunnel environments, in Sweden and several European countries, with focus on the components, the mix design and the guidelines and specifications. It focuses also on the addition of supplementary cementitious materials (SCM), where the use, the common practice and the long-term experience vary from country to country. The report presents numerous examples of applications in Sweden and seven other European countries. It also gives an overview about the possible exposure risks and summarizes the relevant durability issues. Along with specifications in international standards and guidelines it also reviews the national requirements in Sweden, Norway, Finland, Austria, France, Germany and Switzerland.

  • 43. Meng, Birgit
    et al.
    Fontana, Patrick
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Bürgisser, Philip
    Influence of natural pozzolans on the risk of Alkali Silica Reaction2013In: International Conference on Advances in Cement and Concrete Technology in Africa, BAM Federal Institute for Materials and Testing , 2013, p. 801-808Conference paper (Refereed)
  • 44. Miccoli, Lorenzo
    et al.
    Fontana, Patrick
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Ziegert, C
    Perrone MEng, Chiara
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Charakterisierung und Modellierung der mechanischen Eigenschaften von Lehmsteinmauerwerk - Mechanical Characterization and modelling of earth block masonry2012In: Mauerwerk, Vol. 16, no 6, p. 279-292Article in journal (Refereed)
    Abstract [en]

    Knowledge of the material properties and failure mechanisms of earthen materials is limited and scattered. Within the framework of the NIKER project (www.niker.eu) funded by EC, the mechanical properties of earthen material elements were therefore determined under static compression and shear loads. The aim was to obtain fundamental data on deformation behaviour and failure mechanisms of earthen material structural elements and to describe them by means of a numerical model. The test results confirmed the brittle behaviour of earth block masonry under monoaxial compressive load and showed that the failure of earth block masonry under shear load occurs by sliding of the earth blocks along the mortar joints after initial cracking in mortar joints and earth block. Numerical macro modelling showed satisfying results with regard to stress‐strain behaviour, but the simulated crack pattern was not consistent with experimental observations. In the case of earth block masonry, it is thus necessary to use micro modelling approaches in order to correctly predict the failure process at local level.

  • 45. Miccoli, Lorenzo
    et al.
    Fontana, Patrick
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Ziegert, Christof
    Perrone, Chiara
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Charakterisierung und Modellierung der mechanischen Eigenschaften von Lehmsteinmauerwerk - Mechanical Characterization and Modelling of Earth Block Masonry2012In: Masonry, ISSN 1432-3427, E-ISSN 1437-1022, Vol. 16, no 6, p. 279-292Article in journal (Refereed)
  • 46. Miccoli, Lorenzo
    et al.
    Garofano, Angelo
    Fontana, Patrick
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Static behaviour of earth block masonry: experimental testing and Finite Element Modelling2014In: 9th International Masonry Conference (IMC), Guimarães, Portugal, 2014Conference paper (Other academic)
  • 47.
    Miccoli, Lorenzo
    et al.
    BAM Bundesanstalt für Materialforschung und –prüfung, Germany.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Pospíšil, Stanislav
    Institute of Theoretical and Applied Mechanics, Czech Republic.
    Rammed earth walls strengthened with polyester fabric strips: Experimental analysis under in-plane cyclic loading2017In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 149, p. 29-36Article in journal (Refereed)
    Abstract [en]

    This study analyses the mechanical behaviour under pseudo-dynamic loading of structural elements built in rammed earth and strengthened with polyester fabric strips. This strengthening technique was developed to exploit the strength potential of rammed earth and to solve its lack of tensile strength. For this reason, in-plane cyclic tests were carried out to investigate the shear behaviour of unstrengthened and strengthened walls. The strengthening technique requires low-tech equipment and workmanship, uses readily available, not expensive and industrially standardised materials. The experimental results were analysed in terms of stiffness degradation, energy dissipation capacity and equivalent viscous damping. Although the unstrengthened and strengthened walls confirmed a limited ductile behaviour, the findings confirm that the strengthening contributes to limit the spread of the diagonal cracks and provide an increase of strength in terms of horizontal load and displacement capacity.

  • 48.
    Miccoli, Lorenzo
    et al.
    Bundesanstalt für Materialforschung und -prüfung, Germany.
    Silva, Rui
    University of Minho, Portugal.
    Oliveira, Daniel
    University of Minho, Portugal.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Static behavior of cob: Experimental testing and finite-element modeling2019In: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 31, no 4, article id 04019021Article in journal (Refereed)
    Abstract [en]

    The aim of this paper is to implement a numerical model to reproduce the nonlinear behavior of cob walls under shear loading. Axial compression, pull-off, and diagonal compression tests were carried out to derive the mechanical parameters. In addition, the stressstrain relationships, the nonlinear behavior, and the failure modes were defined. The experimental results were then used to calibrate a finiteelement model. The material behavior was simulated through a macromodeling approach adopting the total strain rotating crack model. A sensitivity analysis was conducted to assess the effects of varying the parameters with higher uncertainty on the structural behavior. The numerical model achieved good correspondence with the experimental results in terms of simulation of the shear stress-shear strain relationship and of damage pattern.

  • 49.
    Mueller, Urs
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    The mineralogical composition of sandstone and its effect on sulphur dioxide deposition2008In: Materiales de Construcción, Vol. 58, no 289-290, p. 81-95Article in journal (Refereed)
    Abstract [en]

    Air pollutants often accelerate stone deterioration in historical buildings and monuments in urban areas. The pollutants are themselves the products of fossil fuel combustion and intensive farming. While this trend seems to have been curbed by strict emission laws in the European Union, in most developing and emerging countries air pollution is an ongoing process due to increasing energy needs and vehicle traffic. Many factors condition natural stone behaviour with respect to gaseous pollutants. Two of the more prominent of such factors are the composition of the atmosphere and the type of stone. Due to their porosity, sandstones are particularly vulnerable to air pollutant attack. Many of the reactions between non-carbonaceous sandstones and these gases are not well understood, however. The present study aimed to acquire an understanding of the processes and factors governing sandstone behaviour when exposed to sulphur dioxide. Seven different sandstones from southern and eastern Germany were analyzed for the study. The binder composition of the stones varied significantly. They also exhibited completely different behaviour in connection with SO 2 sorption. Interestingly, while the amount of SO 2 deposited was unrelated to the specific surface area of the sandstones, this parameter was closely correlated to the iron oxide content. Iron oxide phases are believed to act as a catalyst in the oxidation of SO 2 to SO 3 . The type and amount of clay mineral, in turn, was found to have no significant impact on initial SO 2 deposition in sandstones.

  • 50.
    Mueller, Urs
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Lundgren, Monica
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Babaahmadi, Arezou
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Hydration of concrete binders blended with ground granulated blast furnace slag, fly ash and metakaolin2017Report (Other academic)
    Abstract [en]

    This report describes a study on the effects of ground granulated blast furnace slag, low calcium fly ash and metakaolin on the hydration behavior of different binder pastes blended with these SCM. The study investigated early heat development, phase assemblages at different ages, strength gain, changes in porosity and pore sizes, pore water OH-concentration, development of the microstructure and the micro chemistry of the binder pastes.It was shown that all SCM impact the pore size distribution of pastes of different ages. Compared to a reference paste without SCM, SCM containing pastes shift their pore size range to smaller sizes, the more SCM the pastes contain. The total porosity depends on the type of SCM. With slag, there was a tendency to decrease the total porosity with increasing SCM content. With fly ash, total porosity was increased with increasing fly ash content. The strength development of slag and fly ash containing mortars is under that of a Portland cement reference mortar within the first 28 days. However, after 28 d strength gain, in particular with fly ash is considerable compared to the reference. With metakaolin already at early ages a strong increase in strength was observed. After that, the strength development was parallel the one of the reference mortar. Aluminum containing SCM contribute to the formation of AFm phases. AFm phases increase the chloride binding in seawater or deicing salt exposed concretes. In particular metakaolin and fly ash contribute, due to their high alumina content, to the formation of AFm phases but also increase the aluminum content in the C-S-H phases.

12 1 - 50 of 74
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
v. 2.35.7