Concrete structures have the largest surface area of all human made structures. Large surface area makes concrete capable to absorb CO2 from environment during its lifetime. It is estimated that concrete during its lifetime can absorb about 15-20% of CO2 which had produced in cement production. In Sweden the CO2 uptake by concrete construction is estimated to 300 000 tons annually. This study aims to investigate the influences of fly ash and ground granulated blast furnace slag on carbonation. Accelerated carbonation with 65% relative humidity and 10% CO2 concentration was utilized to simulate the carbonation in cement pastes and cement mortars. Series of experiments have accomplished by collaborating with RISE and university of Borås. In this study cement pastes crushed into three fractions in order to evaluate the impact of particle size and influence of blended cement in CO2 uptake. Lastly, carbonation depth of mortars after 14 days accelerated carbonation were analyzed. Experimental results show that the increasing CO2 uptake induced by adding mineral admixture such fly ash in cement pastes. In this study cement paste with 30% fly ash replacement and fraction lower than 2 mm exhibit the highest CO2 uptake compared to other cement paste in this study. Moreover, carbonation depth of cement mortar was also increased three times more in mortar with 30% fly ash compared with mortar with 100% Portland cement. Therefore, incorporation of mineral admixture in cement pastes can improve the CO2 uptake and moreover, CO2 uptake can be more efficient if more surface area be involved with CO2 by crushing cement paste into lower 2 mm. / Betongkonstruktioner har den största ytan av alla människor gjorda strukturer. Stor yta gör att betong kan absorbera CO2 från luften under betongens hela livstid. Det uppskattas att betong under sin livstid kan absorbera cirka 15–20 % av CO2 som hade producerats i cementproduktionen. I Sverige uppskattas CO2-upptaget till 300 000 ton per år. Denna studie syftar till att undersöka den optimala kombinationen som kan påverka karbonatisering. Accelererad karbonatisering med 65% relativ luftfuktighet och 10% CO2-koncentration utfördes för att kunna simulera upptaget av koldioxid i cementpastor och cementbruk. En rad experiment har genomförts tillsammans med RISE och Högskolan i Borås. I denna studie krossades cementpastor i tre olika fraktioner för att utvärdera effekten av kornstorlek och påverkan av cementpastasinnehål i upptaget av CO2. Slutligen analyserades karboneringsdjupen för cementbruk efter 14 dagar accelererad karbonatisering. De experimentella resultaten från accelererad karbonatisering visar att med ökad halt av flygaska kan CO2-upptaget ökas. Cementpastan med 30 % flygaska och fraktionen lägre än två mm uppvisar det högsta CO2-upptaget jämfört med andra cementpastor med grövre fraktioner i denna studie. Dessutom ökade karbonatiseringsdjupet i cementbruk med 30% flygaska cirka tre gånger mer jämfört med cementbruk med 100% Portlandcement. Utifrån dessa resultat kan det konstateras att inblandning av tillsattmaterial i cementpasta kan förbättra CO2-upptaget och dessutom kan CO2-upptaget sker effektivare om mer kontaktytor blir involverade med CO2 genom att krossa cementpastan i fraktionen 0–2 mm.

This study investigates the mechanical differences between old and newly produced slatted floors through a four-point bending test. To understand to what extent the actual environment has affected the slatted floors, the carbonation depth and corrosion will be examined. The tests showed no mechanical differences between slatted floors which had been in service for a certain amount of years and newly produces ones. Corrosion could be observed on some of the samples but it was not because of the carbonation process. When comparing the calculations of reinforced and pre-stressed concrete slatted floors, the result showed that the pre-stressed floor could carry up to double the load of what the reinforced slatted floor could. The conclusion of this study is, that the pre-stressed slatted floors will certainly hold for at least thirty years and will most likely hold for many years to come.