The Influence of Ultrafine Filler Materials on Mechanical and Durability Characteristics of Concrete

This paper aims at investigating the influence of partial replacement of Portland cement with ultrafine fillers compared to limestone powder on the durability and mechanical characteristics of concrete. For this purpose, ultrafine calcium carbonate materials with different specific surface areas of 9.7 and 15.1 m2/g and limestone powder (0.72 m2/g) were used. The results indicate that the ultrafine fillers enhanced the durability properties compared to the mixtures containing limestone. For instance, ultrafine fillers provided up to 20% higher concrete surface resistivity and 20% lower rapid chloride migration test (RCMT) coefficient, while limestone mixes showed equal or even lower durability levels compared to the plain mixture with 0% supplementary cementitious materials. The influence of filler materials on the compressive strength was not significant. However, regardless of the surface area, incorporating filler materials at levels up to 5% led to somewhat higher compressive strengths compared to the plain mixture. Generally, it seems that using finer fillers may lead to more durable concrete mixes.