In English | ISSUE 4/2022




LOIKKA-project aims at reducing CO2-emissions of concrete manufacturing by 50%. The project consists of research project at Aalto University and five industrial projects. As a part of LOIKKA-project Ahsan Iqbal made his master’s thesis on the topic: Durability Properties of Low-Carbon Concretes.

In the experimental program the strength development as well as durability properties of concrete containing different binders was investigated. The slag content of the binders varied between 0% – 80%. The experimental program included compressive strength, freeze-thaw resistance of non-carbonated and carbonated specimens, carbonation depth measurements as well as thin section analyses. Test specimens were prepared and tested according to respective test standards.

Results concluded that slag content had clear effect on different properties of concrete. Concretes with high slag content had lower compressive strength at the age of 7 days, but at 91 days the highest compressive strength was recorded for test concretes with app. 70 % slag content. Moreover, slag had a dominant effect on salt freeze-thaw resistance. 50% slag replacement with cement was considered critical. In addition, carbonation had clear effect on the scaling of concrete. The resistance of carbonated samples was quite low and surpassed the maximum scaled material limits. Frost resistance without chlorides was acceptable even with highest slag contents.

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