DESIGN OF LOW CARBON HIGH PERFORMANCE CONCRETE INCORPORATING ULTRAFINE MATERIALS

Abstract

In general, high performance concrete (HPC) is associated with high strength and improved durability in comparison to normal strength concrete. However, HPC invariably involves high binder content at low water/binder ratio and its application has been limited to specialised concrete works. In this study, an attempt was made to design high performance concrete, at high water/binder ratio made with OPC content varying from 40%-80% in concrete mixes with low binder content of 280 kg/m³. Binary and quaternary, low carbon mixes were prepared by incorporating  Supplementary Cementitious Materials (SCM) and Ultrafine (UF) materials (silica fume, ultrafine GGBS, ultrafine fly ash and metakaolin) and were characterised for strength and durability parameters such as charge passed using RCPT, electrical resistivity and carbonation depth. Findings of the study shows that with appropriate choice and combination of SCM and ultrafine materials, low carbon high performance concrete mixes can be designed for strength up to 50 MPa with improved durability performance even at 45% OPC content. Overall, performance of low carbon high performance concrete mixes depends on the type and extent of SCM as well ultrafine materials such as metakaolin, ultrafine GGBS, ultrafine fly ash and silica fume use along with their compatibility.