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  • 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. 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)
  • 3.
    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)
  • 4.
    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.

  • 5.
    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.

  • 6.
    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.

  • 7.
    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)
  • 8.
    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 restoration2018In: Journal of Cultural Heritage, ISSN 1296-2074, E-ISSN 1778-3674Article 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.

  • 9. 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)
  • 10.
    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.

  • 11.
    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 2234-1315Article 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.

  • 12.
    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).

  • 13.
    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.

  • 14.
    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.
    Torkkeli, Minna
    Finnish Transport Agency.
    Hejll, Arvid
    Swedish Transport Administration.
    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.

  • 15.
    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.
    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.

  • 16.
    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.

  • 17.
    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.

  • 18.
    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: 13th ISRM International Congress of Rock Mechanics: Innovations in applied and theoretical rock mechanics, 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.

  • 19.
    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.

  • 20.
    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.

  • 21.
    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.

  • 22. Lindgård, Jan
    et al.
    Grelk, Bent
    Wigum, Børge Johannes
    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.
    Ferreira, M
    Leivo, Markku
    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)
  • 23.
    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.

  • 24.
    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.

  • 25. 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)
  • 26. 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.

  • 27. 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)
  • 28. 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)
  • 29.
    Miccoli, Lorenzo
    et al.
    Bundesanstalt für Materialforschung und –prüfung (BAM), 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.

  • 30.
    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.

  • 31.
    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.

  • 32.
    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.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Development of pore structure and hydrate phases of binder pastes blended with slag, fly ash and metakaolin – A comparison2015In: The 14th International Conress on the Chemistry of Cement, 2015Conference paper (Refereed)
  • 33.
    Mueller, Urs
    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.
    Influence of hydrophobicity and oleophobicity on cleaning graffiti on concrete panels and natural stones2012In: Concrete Repair, Rehabilitation and Retrofitting III (ICCRRR), TAYLOR and FRANCIS GROUP, LONDON, UK , 2012, p. 269-275Conference paper (Refereed)
    Abstract [en]

    Anti-Graffiti Systems (AGS) are meant to make the cleaning process more efficient by inserting a layer between the paint and the substrate. This layer can have a low surface energy thus make it difficult for the paint to stick to the substrate or it may be easily removed together with the paint. This paper is presenting results from a study of how hydrophobicity and oleophobicity influence the cleaning efficiency of graffiti paints from concrete and natural stones. The results demonstrated that high hydrophobicity and high oleophobicity are not guaranteeing satisfying cleaning effects. The physical properties of a substrate in combination with the characteristics of the AGS layer decide about the cleaning effect.

  • 34.
    Mueller, Urs
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Rübner, Katrin
    The microstructure of concrete made with municipal waste incinerator bottom ash as an aggregate component2006In: Cement and Concrete Research, Vol. 36, no 8, p. 1434-1443Article in journal (Refereed)
    Abstract [en]

    The interaction of municipal solid waste incinerator bottom ash (MSWI bottom ash), when utilized as an aggregate in concrete, with the cement matrix was investigated. The most prominent reaction observed in lab and field concrete was the formation of aluminium hydroxide and the release of hydrogen gas from aluminium grains reacting in the alkaline environment. The expansive aluminium reaction was identified as a main cause of extensive spalling on the concrete surface. Due to the higher content of bottle glass as part of the ash, in all samples, reaction products of an alkali-silica reaction (ASR) could be observed as well. However, damage due to ASR were less severe than those caused by the aluminium reaction. The expansion rates were low and only a few of the lab samples showed cracking. Microstructural analysis of the samples indicated clearly that a large quantity of the alkali-silica gel which was formed was accommodated in the pores and voids without exerting any strain on the material.

  • 35.
    Mueller, Urs
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Schlegel, Moriz-Caspar
    Emmerling, Franziska
    Malaga, Katarina
    Novel techniques for studying damage mechanisms of cementitious matrices affected by sulphate attack2012In: fib symposium Concrete Structures for Sustainable Community / [ed] Bager, D.H., Silfwerbrand, J., 2012, p. 267-270Conference paper (Refereed)
  • 36.
    Mueller, Urs
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Williams Portal, Natalie
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Textile Reinforced Reactive Powder Concrete and its Application for Facades2017Conference paper (Refereed)
    Abstract [en]

    Reactive powder concrete (RPC) is a fairly novel material with extraordinary strength and durability properties. Due to these properties, it is increasingly being utilized also for external facade cladding thus enabling a considerable reduction in the thickness of concrete elements. Commercial RPC formulations on the market have drawbacks in terms of sustainability due to their high clinker content and heat curing which is often applied to increase final strength and material density. The presented study focusses on improved formulations with higher replacement levels of cement clinker by supplementary cementitious materials (SCMs). One different mix formulation was designed and tested in terms of mechanical properties. The formulation was combined with carbon textile reinforcements primarily to enhance the flexural and tensile behavior of the material. The results showed that even with clinker replacement levels of up to 33 % of the total binder amount, a satisfactory mechanical performance of the RPC mix could still be achieved. Fairly steep strength gains rendered heat treatment unnecessary. The incorporation of carbon textile fiber grids proved to be effective in improving the post peak performance of the RPC. However, their performance depended strongly on the bond between the carbon grid and the RPC. Higher moister contents in the concrete proved to reduce the bond strength between the carbon textile and the cement paste. This is maybe less relevant for facades but structural elements with textile reinforcement and RPC might perform less well in completely submerged environment.

  • 37. Månsson, Hans
    et al.
    Henrik, Radomski
    Olenfalk, Pia
    Trägårdh, Jan
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Edwards, Ylva
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Lundgren, Dennis
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Mansfeldt, Nikolaj
    Kinnmark, Mikael
    Nilsson, Alexander
    Norderup Michelson, Elisabeth
    Jutewik, Mikael
    Hellqvist, Peter
    Bylin, Anders
    Ullsten, Åsa
    Wallin, Magnus
    Samuelsson, Hans
    Svenningsson, Catharina
    Gustavsson, Per
    Olofsson, Mikael
    Antonsson, Ulf
    Skärin, Jörgen
    Lejonmark, Sebastian
    Grönatakhandboken: Betong, isolering och tätskikt2017Report (Other academic)
  • 38.
    Plos, Mario
    et al.
    Chalmers University of Technology, Sweden.
    Shu, Jiangpeng
    Chalmers University of Technology, Sweden.
    Zandi, Kamyab
    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.
    A multi-level structural assessment strategy for reinforced concrete bridge deck slabs2017In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 13, no 2, p. 223-241Article in journal (Refereed)
    Abstract [en]

    This paper proposes a multi-level assessment strategy for reinforced concrete bridge deck slabs. The strategy is based on the principle of successively improved evaluation in structural assessment. It provides a structured approach to the use of simplified as well as advanced non-linear analysis methods. Such advanced methods have proven to possess great possibilities of achieving better understanding of the structural response and of revealing higher load-carrying capacity of existing structures. The proposed methods were used for the analysis of previously tested two-way slabs subjected to bending failure and a cantilever slab subjected to a shear type of failure, in both cases loaded with concentrated loads. As expected, the results show that more advanced methods yield an improved understanding of the structural response and are capable of demonstrating higher, yet conservative, predictions of the load-carrying capacity. Nevertheless, the proposed strategy clearly provides the engineering community a framework for using successively improved structural analysis methods for enhanced assessment in a straightforward manner.

  • 39.
    Sykora, Miroslav
    et al.
    Czech Technical University in Prague, Czech Republ.
    Krejsa, Jan
    Czech Technical University in Prague, Czech Republ.
    Mlcoch, Jan
    Czech Technical University in Prague, Czech Republ.
    Prieto Rábade, Miguel
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Tanner, Peter
    Instituto de Ciencias de la Construcción EduardoTorroja, Spain.
    Uncertainty in shear resistance models of reinforced concrete beams according to fib MC20102018In: Structural Concrete, ISSN 1464-4177, E-ISSN 1751-7648Article in journal (Refereed)
    Abstract [en]

    Load bearing capacity can be predicted by appropriate modeling of material properties, geometry variables, and uncertainties associated with an applied model for the failure mechanism under consideration. The submitted study investigates shear resistance model uncertainties for reinforced concrete beams with and without shear reinforcement, considering large test databases and various levels of approximation offered by fib Model Code 2010. Model uncertainty is treated as a random variable and its characteristics are obtained by comparing test and model outcomes. The sensitivity of model uncertainty with respect to basic variables is analyzed. For beams with stirrups, Level III is recommended for practical applications. Its predictions are shown to be independent of the amount of shear reinforcement and have reasonable bias and dispersion around test results. For beams without shear reinforcement, the use of Level II is advisable and a distinction between lightly reinforced and moderately to heavily reinforced beams should be made.

  • 40.
    Tahershamsi, M.
    et al.
    Chalmers University of Technology, Sweden.
    Fernandez, I.
    Chalmers University of Technology, Sweden.
    Lundgren, K.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Zandi, Kamyab
    RISE, SP – Sveriges Tekniska Forskningsinstitut, CBI Betonginstitutet AB, Betong & Berg. Chalmers University of Technology, Sweden.
    Investigating correlations between crack width, corrosion level and anchorage capacity2017In: Structure and Infrastructure Engineering, ISSN 1573-2479, E-ISSN 1744-8980, Vol. 13, no 10, p. 1294-1307Article in journal (Refereed)
    Abstract [en]

    In assessing existing structures, inspection results need to be linked to the effects on load-carrying capacity; to provide such information, this study has investigated the correlation between splitting crack width, corrosion level and anchorage capacity. The study was based on 13 reinforced concrete beams that had been exposed to natural corrosion for 32 years, 11 beams with splitting cracks and 2 without. The crack pattern and widths were documented before undergoing structural testing of anchorage capacity. Thereafter, the reinforcement bars were extracted and their corrosion levels measured using two methods, gravimetric weight loss and 3D scanning. The corrosion level from the weight loss method was approximately twice as large; possible reasons are horizontal or subsurface corrosion pits, and the cleaning method. Further, for the same corrosion level, the specimens in this study had much larger crack widths and slightly lower bond capacity than the artificially corroded tests in the literature; a possible reason is that these specimens had been subjected to combined corrosion and freezing. However, the corrosion level and reduction in bond capacity related to crack width were both lower in the present than in previous studies in the literature. Thus, by formulating a damage indicator from the damage visible in the form of crack widths from artificial test data, the structural capacity is estimated to be on the safe side.

  • 41.
    Tahershamsi, M.
    et al.
    Chalmers University of Technology, Sweden.
    Fernandez, I.
    Chalmers University of Technology, Sweden.
    Zandi, K.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Lundgren, K.
    Chalmers University of Technology, Sweden.
    Four levels to assess anchorage capacity of corroded reinforcement in concrete2017In: Engineering structures, ISSN 0141-0296, E-ISSN 1873-7323, Vol. 147, p. 434-447Article in journal (Refereed)
    Abstract [en]

    Corrosion of reinforcement affects anchorage capacity. In this study, four levels of analyses were, for the first time, compared with each other and to tests of naturally corroded beams. In the most advanced approach, three-dimensional non-linear finite element (3D NLFE) analyses employing previously developed bond and corrosion models were carried out. These analyses agreed well with the experiments in terms of crack pattern and maximum load capacity. The next approach consisted of 3D NLFE analyses with a pre-defined bond-slip relation between concrete and reinforcement, resulting in reasonable agreement; however, the anchorage capacity was overestimated and the crack pattern deviated from the experiments. At the next level, the bond-slip relation was used together with a measured available anchorage length, and the anchorage capacity was obtained by numerically solving the one-dimensional differential equation; the results were reasonably close to the experiments. In the most simplified approach, a constant bond stress was assumed together with the available anchorage length measured, which underestimated the capacities. In conclusion, the more advanced analyses provide reliable information regarding the structural behaviour, while the two simplified methods are well suited for use in practice.

  • 42.
    Wallqvist, Viveca
    et al.
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Kjell, G.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Cupina, Ena
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials. Chalmers Univeristy of technology, Sweden.
    Kraft, Lars
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Deck, C.
    University of Strasbourg, France.
    Willinger, R.
    University of Strasbourg, France.
    New functional pavements for pedestrians and cyclists2017In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057, Vol. 105, p. 52-63Article in journal (Refereed)
    Abstract [en]

    When many fields of pedestrian and cyclist safety have been extensively studied, the surfacing has long been left unquestioned, despite being developed for another mode of transport and being one of the main causes for falls and fall injuries. In this project new surfacing materials for pedestrian and cyclist safety have been produced. Focusing on augmenting previously largely disregarded parameters as impact absorption, comfort and visibility at the same time as avoiding deteriorating of crucial parameters as friction and wear resistance. Rubber content, binder type, and pigment addition have been varied and evaluated. The results demonstrate that by increasing rubber content of the mixtures the head injury criterion (HIC) value and injury risk can be decreased while maintaining frictional properties according to existing criteria. Assembly of test-lanes demonstrate that some developed materials experience lower flow and component separation than standard materials due to rubber addition, calling for further optimisation of construction procedure linked to content development. Initial trials on the test-lanes indicate that a polyurethane (PU) based material has high cycling comfort, visibility and can be modified with phosphorescence properties. For standard asphalt, impact absorption might be inflicted by modification of bitumen alone but is mostly augmented by rubber addition. The results also indicate that rubber content can decrease ice formation on the materials.

  • 43.
    Werder, Julia
    et al.
    Bundesanstalt für Materialforschung und ‐prüfung, Germany.
    Simon, Sebastian
    Bundesanstalt für Materialforschung und ‐prüfung, Germany.
    Lehmann, Christian
    TU Berlin, Germany.
    Selleng, Christian
    TÜV Nord MPA, Germany.
    Fontana, Patrick
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Meng, Birgit
    Bundesanstalt für Materialforschung und ‐prüfung, Germany.
    Autoclaving of ultra-high performance concrete (UHPC)2018In: ce/papers, ISSN 2509-7075, Vol. 2, no 4, p. 131-136Article in journal (Refereed)
    Abstract [en]

    Abstract By the combination of an optimized granulometry, a reduced water?cement ratio and the use of superplasticizers ultra-high performance concrete achieves a compressive strength of over 150 N/mm2 and a high resistance regarding acids and water-soluble salts. In different research projects the effect of an autoclavation on the mechanical strength and the phase composition was analyzed. In systematic studies, the concrete mix and the process parameters were varied. The results show that autoclavation leads to an improved pozzolanic and hydraulic reaction and significantly improves the mechanical strength compared to a conventional thermal treatment. If a minimum time-span for hydration is ensured, the achievable strength level is not dependent on the prestorage time. However, the duration of the autoclaving is significant. After the maximum strength is reached there is only a very slight decrease, even if unrealistically long autoclaving times are applied.

  • 44.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Flansbjer, Mathias
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Malaga, Katarina
    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.
    Anchorage of Textile Reinforcement in High-Performance Concrete2017Conference paper (Refereed)
    Abstract [en]

    The mechanical properties of textile reinforced high-performance concrete (TRHPC) applied in innovative lightweight sandwich elements has been investigated in the framework of EC supported FP7 project, H-House (Healthier Life with Eco-innovative Components for Housing Constructions). TRHPC offers new possibilities for architects and engineers to create thinner and more durable concrete façade elements. Textile reinforcement grids are typically woven from non-metallic rovings usually consisting of continuous glass, rock or carbon fibres. The most promising performing textile reinforcement alternative in terms of mechanical and durability performance consists of carbon fibres. Carbon fibres do however have an inherent smooth surface which is unfavourable concerning its bond to the cement paste, which is often improved by polymer-based coatings. The bond behaviour, being a critical design parameter, should be investigated for TRHPC in order to understand limitations regarding required anchorage lengths for use in applications such as façade elements. The aim of this study was to quantify and verify the required anchorage length for a selected epoxy impregnated carbon textile reinforced TRHPC combination. To achieve this aim, the bond behaviour, leading to a suitable anchorage length (or overlap), was firstly studied by means of pull-out tests. Thereafter, the ultimate strength of the composite material was measured via uniaxial tensile testing with and without an overlap splice according to the findings from the pull-out tests. Optical measurements during the pull-out tests were performed using a video extensometer technique and by Digital Image Correlation (DIC) for the uniaxial tensile tests. Results indicated that the required anchorage length to yield rupture of the textile reinforcement in pull-out was deemed appropriate as an overlapping length when tested in tension. The combination of these two experimental methods on the composite level was useful for determining the overlapping length required for the TRHPC which could be applied in larger scale applications.

  • 45.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Flansbjer, MathiasRISE - Research Institutes of Sweden, Safety and Transport, Safety.Mueller, UrsRISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Analysis of the Flexural Behavior of Textile Reinforced Reactive Powder Concrete Sandwich Elements Using Optical Measurements2018Conference proceedings (editor) (Refereed)
    Abstract [en]

    Prefabricated and non-load bearing sandwich façade elements were developed using Textile Reinforced Reactive Powder Concrete (TRRPC) along with low density Foamed Concrete (FC) and Glass Fiber Reinforced Polymer (GFRP) continuous connecting devices. Four-point bending tests were performed on large-scale TRRPC sandwich element beams to characterize the structural performance, which included the flexural capacity, level of composite action, resulting deformation, crack propagation and failure mechanisms. Optical measurements based on Digital Image Correlation (DIC) were taken simultaneously to enable a detailed analysis of the underlying composite action. The structural behavior 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.

  • 46.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Safety and Transport, Safety.
    Flansbjer, Mathias
    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.
    Experimental Study on Anchorage in Textile Reinforced Reactive Powder Concrete2017In: Nordic Concrete Research, ISSN 0800-6377, Vol. 57, no 2, p. 73-88, article id 6Article in journal (Refereed)
    Abstract [en]

    The EC funded project SESBE (Smart Elements for Sustainable Building Envelopes) focused on utilizing new types of cementitious materials for reducing the mass and thickness of façade elements while increasing their thermal performance. A method enabling the quantification and verification of the required anchorage length for a given textile reinforced reactive powder concrete (TRRPC) is presented. At the material level, tensile tests were conducted to determine the tensile properties of the reinforcement. Pull-out tests were applied to quantify the required anchorage length, while uniaxial tensile tests were performed to quantify the ultimate strength and verify the suitability of the anchorage length at the composite level. The combination of these methods was deemed useful to determine the overlapping length required for larger scale façade applications.

  • 47.
    Williams Portal, Natalie
    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.
    Zandi, Kamyab
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Wlasak, Lech
    Mostostal Warszawa S.A., Poland.
    Malaga, Katarina
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Bending behaviour of novel Textile Reinforced Concrete-foamed concrete (TRC-FC) sandwich elements2017In: Composite structures, ISSN 0263-8223, E-ISSN 1879-1085Article in journal (Refereed)
    Abstract [en]

    A novel sandwich element design consisting of two facings made of carbon reinforced Textile Reinforced Concrete (TRC), a low density foamed concrete (FC) core and glass fibre reinforced polymer (GFRP) connecting devices was experimentally investigated according to quasi-static and cyclic quasi-static fourpoint bending. Optical measurements based on Digital Image Correlation (DIC) were taken during testing to enable a detailed analysis of the bending behaviour and level of composite action. A model, verified by the experiments, was developed based on non-linear finite element analysis (NLFEA) to gain further insight on the failure mechanisms. Under both loading conditions, the bending behaviour of the TRCFC composite elements was characterized by favourable load bearing capacity, partial composite action, superior ductility and multiple fine cracking. The connecting devices were found to be the critical elements causing the initial failure mechanism in the form of localized pull-out within an element.

  • 48.
    Williams Portal, Natalie
    et al.
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute. Chalmers University of Technology, Sweden.
    Nyholm Thrane, Lars
    Technical University of Denmark, Denmark.
    Lundgren, Karin
    Chalmers University of Technology, Sweden.
    Flexural behaviour of textile reinforced concrete composites: experimental and numerical evaluation2017In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 50, no 4, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Textile reinforced concrete (TRC) is an innovative high performance composite material which has revealed many promising attributes in various applications but test methods and reliable numerical models need to be established to reduce uncertainty and the need for extensive experimental studies. The aim of this paper was to evaluate the flexural behaviour of carbon textile reinforced TRC slabs both experimentally and numerically along with the characterization of the material and interaction level properties. The experimental results characterizing the bond behaviour were linked to the experimental behaviour of a rectangular TRC slab in bending through numerical analyses. A 2D macro-scale FE-model of the tested TRC slab was developed based on the related experimental input. Comparison of the numerical results to the experiments revealed that the flexural failure was governed by bond, and reasonable agreement was obtained in terms of crack development, deflections, maximum load, and failure mode. Accordingly, the experiments further indicated that the flexural behaviour of TRC slabs is greatly influenced by the bond quality.

  • 49.
    With, G. D.
    et al.
    Rapporteur to CEN/TC351/WG3 Nuclear Research and Consultancy Group (NRG), The Netherlands.
    Michalik, B.
    Central Mining Institute (GIG), Poland.
    Hoffmann, B.
    Federal Office for Radiation Protection (BfS), Germany.
    Döse, Magnus
    RISE - Research Institutes of Sweden, Built Environment, CBI Swedish Cement and Concrete Research Institute.
    Development of a European harmonised standard to determine the natural radioactivity concentrations in building materials2018In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 171, p. 913-918Article in journal (Refereed)
    Abstract [en]

    In 2013 the European Commission has published its latest basic safety standards for protection against the dangers arising from exposure to ionising radiation (Council Directive 2013/59/Euratom). The council directive regulates radiation exposure from building materials through the presence of radioactivity (226Ra, 232Th and 40K) in these materials. Pivotal to successful regulation is the availability of a harmonised test method for the determination of the radionuclide concentrations as these nuclides form the basis for dose assessment and compliance. In 2017 a Technical Specification (CEN, 2017) on the determination of the activity concentrations of 226Ra, 232Th and 40K in construction products was published by the European Committee for Standardization (CEN). The purpose of this work is to give an outline of the proposed method, with the protocols for sampling, measurement and data processing as well as a summary of the robustness testing and the expert comments that have been received following the final consultation. 

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