Effect of limestone filler BET(H2O)-area on the fresh and hardened properties of self-compacting concrete

This paper presents a study on the use of limestone fillers with different specific surface area and their effect on the fresh and hardened properties of self-compacting concrete (SCC). The surface area was determined by a simplified BET method using water vapour as adsorbate. A rheometer and a slump flow test were used to measure the flowability of fresh concrete. A concrete dilatometer was used to measure the autogenous shrinkage, and a ring-test for the plastic cracking tendency. The compressive strength was determined at 28 days. It was found that the measure of BET(H2O)-area can be used to evaluate the water requirement for constant workability of the SCC, where a change in BET(H2O)-area of 1000 m2/kg corresponds to approximately 0.8% in moisture content. The results showed that filler with a large area will result in an increased autogenous shrinkage, decreased evaporation, lower plastic cracking tendency, and a higher compressive strength. With additional water the results was the opposite.