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.

Det finns i Sverige en lokal brist på naturgrus. Dessutom vill man av miljöskäl bevara kvarvarande naturgrusförekomster. Krossat berg utgör det mest realistiska alternativet till naturgrus. Krossballast skiljer sig från naturgruset genom annorlunda kornkurva, kornform och partikelyta. Krossballast har ofta en betydligt högre andel filler som kan medföra att betongens gjutbarhet försämras kraftigt. Det är dock tekniskt möjligt att påverka andelen filler i slutprodukten genom styrning av krossutrustningen och genom vindsiktning. Krossat berg speciellt som finballast, kommer vid nuvarande proportioneringsmetodik att medföra ett ökat cementbehov vid en given kvalité uttryckt som hållfasthet.  Krossat berg är emellertid ingen enhetlig produkt. Det finns flera olika metoder för krossning och olika typer av bergarter ger olika produkter med olika grad av lämplighet för betong. I Sverige ligger för närvarande bergtäkterna huvudsakligen i granitiskt berg. Som grovballast har granitiskt berg sedan länge använts som betongballast, men nu måste krossmaterialet användas till finballast. Det är känt sedan tidigare att krossat granitiskt berg som finballast kan ställa till med problem. Det beror framför allt på att krossprodukten oftast innehåller flakigt finmaterial och stora mängder filler. Det finns emellertid graniter vars krossprodukt enkelt kan ersätta naturgrus medan det finns graniter som är helt olämpliga.  Bergartstextur och mineralogi avgör kornform och ytstruktur. Man kan finna krossprodukter som fungerar i betong lika bra som naturballast men variationen är mycket stor. Metoder att fragmentera berget påverkar framför allt de grövre partiklarnas kornform och yta medan de finaste partiklarnas kornform och yta bestäms av vilka mineral som ingår i bergarten.  Granit består av en viss uppsättning mineral, framför allt kvarts, fältspat, plagioklas och glimmer som i finfraktionerna ger fria mineral. Det stora problemet med granitiskt krossmaterial är finmaterialet, och då framför allt halten av fri glimmer. Bildanalys visar att det är halten glimmer företrädesvis i form av biotit som styr kornformen som i sin tur kan korreleras mot reologi och arbetbarhet.  Det genomförda arbetet visar prov på hur man på ett relevant sätt kan karakterisera krossprodukter. Materialkarakteriseringen korreleras sedan mot olika typer av enklare ställföreträdande metoder för praktisk provning. Dessa korreleras i sin tur mot reologi och arbetbarhet som ger lämplighet för användning i betong. Materialkarakteristiken kan användas för att selektera berg, optimera processer och finna kostnadseffektiva metoder för resurssnål optimering.  I grunden handlar proportionering om att finna en till kornformen optimerad gradering. En färsk betong är en partikelslurry där de olika fragmenten rör sig mot varandra. En flakig och kantig partikel behöver mera av finare material och vatten för att kunna röra sig än en rund. Detta gäller i alla fraktioner ner till det finaste materialet. För att finna denna kurva har ett databaserat proportioneringsverktyg tagits fram. Skillnaden mellan detta program och andra på marknaden befintliga proportioneringsprogram är att det bättre tar hänsyn till kornformen vilket är det stora problemet vid övergång från naturgrus till krossprodukter. I grunden beräknar det hur stort hålrum som behöver fyllas med mikrobruk (<0,125 mm) för att partikelmassan skall röra sig. Ett mindre hålrum kräver mindre cement för samma hållfasthet. I nästa steg optimeras mikrobruket. Även här gäller det att partiklarna har en så rund/kubisk form som möjligt och metodik för att kvantifiera detta finns redovisad i rapporten. Med hjälp av proportioneringsverktyget och de metoder som anges och har undersökts i rapporten kan man finna metoder att klassificera krossballasten så att man kan proportionera optimalt.  Med hjälp av krossningsmetodik (VSI-krossning) kan man få mera kubiska korn ner till mineralgränsen, dvs., den storlek när fria mineral börjar bli vanligast förekommande. VSI-6(119)metoden bygger på att partiklar sluggas mot en bädd av partiklar vilket ger mera nötning vilket tar bort kanter vilket i sin tur ger mera runda/kubiska partiklar. I vilken storleksfraktion mineralgränsen ligger beror på bergartens grovlek. Fri glimmer är normalt vanlig i fraktioner under runt 0,5 mm. Man kan även minska halten glimmer genom att vindsikta materialet och ersätta fillerfraktionen med något annat. Vid vindsiktning så släpps partiklar i en luftström vilket gör att lätta små partiklar kan separeras från större och tyngre fragment. Det finns även andra klassificeringsmetoder som används inom industrier som arbetar med malm och industrimineral men de blir dyrbara för normal ballastframställning.  Halten glimmer i olika graniter varierar kraftigt från nästan inget till 20–30 %, halter som återspeglas i form av fri glimmer i finfraktionerna. De bergarter som är glimmerfattiga ger det bästa finmaterialet och man kan med hjälp av kubisering och justering av kornkurvan tillverka bra betong med det. En först åtgärd när det gäller krossgrus är därför att finna ett bra berg med låg glimmerhalt. Kalksten och basiska bergarter ger ofta bättre sand än graniter men de kan ge andra problem.  För att kunna spara cement måste man beakta pastafasens egenskaper och hur man kan öka dess volym utan att behöva höja cementhalten. Provningar har visat att man kan minska halten cement utan att sänka hållfastheten genom att öka fillermängden samtidigt som vct hålls konstant. Detta kräver emellertid att man höjer mängden flytmedel och att fillern är av god kvalité, dvs. innehåller runda/kubiska partiklar.  Betongproduktion kräver en jämn kvalité på ballasten. Det finns en mängd metoder för att säkerställa detta men då variationen mellan olika krossprodukter är stor krävs att man först gör en genomlysande analys för att få fram den specifika ballastens problem och därefter tar fram metoder för kvalitetskontroll. Olika metoder för provning och karakterisering av speciellt finballast är beskrivna, testade och korrelerade med framför allt reologiska mätningar i rapporten. Med utgångspunkt från dessa kan man värdera olika typer av krossprodukter och därifrån finna sätt att förbättra egenskaperna.

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.