Potential Strength and Durability of Blended Low-Grade Limestone Calcined Clay Cement Concrete

In the ternary cementitious systems, limestone along with calcined clay shows good mechanical and durability performance at a lower clinker factor as compared to the ordinary Portland cement (OPC) concrete system. The amount of cement-grade limestone in mine reserves is decreasing as the demand for cement rises. This makes it important to explore the potential of low-grade limestone rejected by cement industries during clinker production. This work focuses on the use of rejected limestone along with calcined clay in ternary cementitious systems. The experimental work includes clinker substitutions of 30 wt% and 45 wt% with calcined clay and limestone in 2:1 proportion. Mechanical properties such as compressive strength and durability parameters of concrete like chloride migration and surface resistivity were assessed. The results indicate that 30% ternary blended concrete mix has better compressive strength and durability as compared to ordinary Portland cement concrete mix and the 45% ternary mix has very good durability performance. The overall performance of LC3 based mixes was similar, irrespective of the type of limestone used in the blends. This implies that dolomitic limestone based LC3 blends can be successfully used in producing durable concrete.