The reference level for effective dose due to gamma radiation from building materials and construction products used for dwellings is set to 1 mSv per year (EC, 1996, 1999), (CE, 2014). Given the specific conditions presented by the EC in report 112 (1999) considering building and construction materials, an I-index of 1 may generate an effective dose of 1 mSv per year. This paper presents a comparison of the activity concentrations of 4 0K, 226Ra and 232Th of aggregates and when these aggregates constitute a part of concrete. The activity concentration assessment tool for building and construction materials, the I-index, introduced by the EC in 1996, is used in the comparison. A comparison of the I-indices values are also made with a recently presented dose model by Hoffman (2014), where density variations of the construction material and thickness of the construction walls within the building are considered. There was a ~16-19% lower activity index in concretes than in the corresponding aggregates. The model by Hoffman further implies that the differences between the I-indices of aggregates and the concretes' final effective doses are even larger. The difference is due, mainly to a dilution effect of the added cement with low levels of natural radioisotopes, but also to a different and slightly higher subtracted background value (terrestrial value) used in the modeled calculation of the revised I-index by Hoffman (2014). Only very minimal contributions to the annual dose could be related to the water and additives used, due to their very low content of radionuclides reported.

Eco-neighborhoods with gardens on concrete decks are for several reasons increasingly being prescribed today in major Swedish cities. However, there is a lack of knowledge, experience, standards and guidelines as well as collaboration between parties and stakeholders when installing such systems. It is incredibly important to avoid any leakage during the lifetime of a green roof garden but this cannot be completely guaranteed with today’s installation practice and project management. At Sustainable City 2014 in Siena, we presented a paper about a new project aiming at bringing together researchers, government and industry to collaborative development of new and attractive solutions for green roof gardens with consideration to the environment and high requirements for durability, materials, construction and energy efficiency. This paper is a continuation of the paper presented in Siena and reports on the most recent results from the collaborative project which will finalize in November 2016. After that, the project will be further evaluated in a proposed continuation project for another couple of years.

Particle motion in fluid is discussed for one-particle systems as well as for dense suspensions, such as cementitious materials. The difference in large particle motion between larger particles and behaviour of fines (<125 μm) is explained, motion of one particle is shown by numerical simulation. It is concluded and highlighted that it is the particular motion of the fines that to a large extent contribute to the rheological properties of a suspension. It is also shown why larger ellipsoidal particles do not necessarily contribute to the increase of viscosity.

In Sweden there is a local shortage of natural aggregate. Moreover, for environmental reasons remaining natural aggregate should be preserved. Crushed rocks are the only economically realistic alternative. Aggregate from crushed rocks is different from natural aggregate as regard particle distribution, grain shape and particle surface. Crushed rocks mostly generate a larger amount of filler. That will affect the workability of concrete. In part it is possible to change the particle distribution and particle shape but in general with present rules for concrete proportioning crushed rocks and especially the fine material from crushed rocks will increase the cement demand at a given quality.  Aggregate from crushed rocks is, however, not a uniform product. There are several methods for crushing and different types of rocks that will give different products with different degree of suitability for concrete production.  Different types of granites have since long been the prime source of rock for aggregate in Sweden. Earlier, however, only the coarse aggregate has been from crushed rocks but today Sweden has to learn also to use fine aggregate from crushed rocks. Crushed granites often give bad fine aggregate mainly due to that it contains flaky minerals and generate large amount of filler. The variation is, however, large and some crushed granites give aggregates that is good while other give fine aggregates that con not be used in concrete production. 7(119)  The analysis and tests in this report show how it is possible to characterize crushed rocks. The material characterization is correlated to substitute methods for practical testing. These are in turn correlated to rheological measurements and workability tests. The material characterization can be used to select rock, optimizing processes and to find more cost-effective methods for sustainable concrete optimization.  Granites are composed of a certain set of minerals, mainly quartz, alkali feldspar, plagioclase and micas (muscovite and biotite). In the finer fractions the micas become free and free mica is flaky. Free mica affects the rheology and workability negatively.  Basically, concrete proportioning is about finding an optimized particle size distribution that considers the particle shape. A fresh concrete is a particle slurry where the different grains interfere. A flaky and angular particle needs finer material and water to flow than a round one. This is the case from the course down to the finest material. To find the appropriate distribution curve a computer based proportioning tool has been developed. The difference between this program and earlier similar programs is that it also considers the particle shape. Basically, it calculates the void volume needed to be filled with micro mortar (< 125 μm) to allow flow. Less void demands less cement for the same strength. In the second step the micro mortar is optimized.  Analysis and tests show that the crushing technique is important. With VSI (Vertical Shaft impact) crushing it is possible to get more cubic grains down to the mineral limit, i.e. the size where free minerals dominate over rock particles. Free mica is common in sizes less than 0.5 mm but it depends on the coarseness of the rock. It is possible to lower the amount of micas and filler by wind sieving that separates light and fine particles from coarser but this demands that the fine fraction is replaced. The amount of free micas in the fine fraction varies from almost nothing up to 20-30 % in granites. Thus, it is important to find and use rocks with low contents of mica in aggregate production. Carbonate and basic rocks generally give better fine aggregates than granitic rocks but they can give other problems.  To be able to reduce the amount of cement the properties of the micro mortar have to be considered. Tests have shown that it is possible to lower the strength by increasing the amount of filler and keeping the water/cement ratio constant. This, however, demands a filler of good quality and the use of efficient superplasticizer. Like with the other particles good quality filler is made up of round or cubic particles.  Concrete production demands a uniform and good quality of the aggregate. One of the major problems is inhomogeneities of the rock. As different rocks give different products this demands a geological characterization of the rock. As different rocks give different products it is difficult to give a specific test procedure. Especially the properties of fine aggregate are correlated with rheology and workability. Different methods for testing and describing both rock and products are given in this report. Each quarry has to be characterized and an appropriate quality test procedure has to be established. With data given in this report it is possible to characterize and evaluate different products and from this to find ways to improve the properties.

A large part of the energy consumption in the European Union member states is related to space heating, a significant share of which is due to transmission losses through the building envelope. Vacuum insulation panels (VIPs), with unique thermal insulation properties, do therefore provide an interesting alternative for the building industry. This paper presents the results of a life cycle analysis (LCA) study that compares the environmental impact of three hypothetical buildings, a standard residential building, a regular well-insulated building and a building insulated with VIPs. The environmental impact includes the global warming potential (GWP) and the primary energy (PE) use, from the material production stage to the building operational phase (50 years). The cradle-to-gate environmental impact categories of ozone depletion potential (ODP), acidification potential (AP) and eutrophication potential (EP) of all building components are also assessed. The study shows a comparatively lower operational energy for the VIP insulated building and a relatively lower total greenhouse gas emission as well as the possibility to save significant living space. The results also show that the VIPs have measurable environmental impact during the product stage while the core material of the VIPs has considerable impact on the results.

Concrete is the most common and widely used construction material in the world, with a consumption of approximately 1.5 tons per capita annually worldwide. This consumes 3000 million ton of cement, around 400 kg per capita. Sweden consumes around 250 kg of cement per capita.  The production of Portland cement consumes around 3500 MJ energy per ton. In addition, Portland cement production releases considerable amounts of CO2 when limestone is heated and calcinated. With 800 kg of CO2 per ton of cement around 5 % of the global release of CO2 comes from cement clinker production. About half of this comes from the limestone. Concrete, however, also binds CO2 when it is carbonated. In a geological time perspective, all concrete will carbonate and thus half of the released CO2 will be bound to carbonated concrete, which would reduce the environmental impact (Xi et al 2016). I reality the absorption is much less, and is related to the time interval of interest.  How fast CO2 will be absorbed depends on the type of concrete or cementitious material, site of the concrete, amount of CO2 in the environment and the environment as such, etc. It is also depending on the amount CO2 in the atmosphere and the temperature. In the end, to be able to calculate the uptake it is important to find out what happens with the concrete after demolition and if it is possible to increase the speed of carbonation.  This report mainly cover the mechanism and mode of carbonation to be able to get a better and more accurate understanding of how to calculate carbonation and CO2 uptake.  This project was funded by the Swedish Consortium for financing Basic research in the Concrete Field. The consortium members are: Cementa, Färdig Betong, Abetong, Swerock, Betongindustri and Strängbetong.

First, we define in this paper two benchmark flows readily usable by anyone calibrating a numerical tool for concrete flow prediction. Such benchmark flows shall allow anyone to check the validity of their computational tools no matter the numerical methods and parameters they choose. Second, we compare numerical predictions of the concrete sample final shape for these two benchmark flows obtained by various research teams around the world using various numerical techniques. Our results show that all numerical techniques compared here give very similar results suggesting that numerical simulations of concrete filling ability when neglecting any potential components segregation have reached a technology readiness level bringing them closer to industrial practice.

This paper presents some durability and service life models for reinforced concrete structures with regard to chloride ingress, carbonation and frost attack. In the past years a number of models for durability design of concrete structures have been suggested by relevant organisations or international committees. It is necessary to validate these models against long-term field data for their applicability with respect to exposure climate in order to satisfactorily use the models in the durability design and redesign of concrete structures. In this study, various potential models for concrete resistance to chloride ingress, carbonation and frost attack were briefly reviewed. Three models including the simple ERFC, the DuraCrete and the ClinConc, for prediction of chloride ingress were evaluated using the infield data collected from both the field exposure site after over 20 years exposure and the real road bridges of about 30 years old. A physicochemical model for prediction of carbonation depth was evaluated using the infield data collected from the field exposure site after 11 years exposure and the limited data from the real structures with the age of 7-13 years. For the modelling of frost attack, some problems in measurement of critical saturation degree and actual degree of saturation are discussed. According to the comparison results, the simple ERFC overestimates whilst the DuraCrete model underestimate the chloride ingress in most cases. The ClinConc model on the other hand gives reasonable good prediction for both the short-term (one year) and the long-term (21 years) exposure. The Papadakis model for carbonation also gives fairly good prediction of carbonation depth when compared with the Norwegian infield data classified as exposure class XC3|, but underestimates the carbonation depths when compared with the infield data from Norwegian structures in exposure class XC4.

Calcination of carbonate rocks during the manufacture of cement produced 5% of global CO 2 emissions from all industrial process and fossil-fuel combustion in 2013. Considerable attention has been paid to quantifying these industrial process emissions from cement production, but the natural reversal of the process - carbonation - has received little attention in carbon cycle studies. Here, we use new and existing data on cement materials during cement service life, demolition, and secondary use of concrete waste to estimate regional and global CO 2 uptake between 1930 and 2013 using an analytical model describing carbonation chemistry. We find that carbonation of cement materials over their life cycle represents a large and growing net sink of CO 2, increasing from 0.10 GtC yr â '1 in 1998 to 0.25 GtC yr â '1 in 2013. In total, we estimate that a cumulative amount of 4.5 GtC has been sequestered in carbonating cement materials from 1930 to 2013, offsetting 43% of the CO 2 emissions from production of cement over the same period, not including emissions associated with fossil use during cement production. We conclude that carbonation of cement products represents a substantial carbon sink that is not currently considered in emissions inventories.

Cathodic prevention (CPre) technique is a promising method and has been used for the past two decades to prevent steel from corrosion in concrete structures. However, wide application of this technique has been restricted due to high costs of anode materials. In order to lower the cost and further improve this technique, carbon fiber composite anode has been introduced as an alternative anode material with affordable price and other outstanding properties. This paper presents the study of using carbon fiber mesh as anode material for long-term cathodic prevention system and the effect of accelerated current on macro- And microstructure of cementitious materials. In the study, electrochemically accelerated tests were developed for the purpose of shortening the experimental time into a manageable range. An estimation tool was used to predict the service life as well. Chemical and microstructure analyses were carried out by laser-ablation inductively-coupled-plasma mass-spectroscopy (LA-ICP-MS) and scanning electron microscope (SEM). Results indicate that calcium to silicon (Ca/Si) ratio and ion re-distribution in the current-affected zone around the anode were changed due to migration and electrochemical reactions. The predicted service life was in general longer than 100 years. Based on the results from this work, it can be concluded that carbon fiber mesh is suitable for the application as anode in long-term cathodic prevention system in cementitious materials.