Strength and microstructure characteristics of low-grade (LG) limestone-based cements for a sustainable concrete

The primary objective of this study is to make use of moderate and low-grade limestone in cement manufacturing for sustainable and economic benefits. In the present work, limestone from clinkers of different grades is explored for producing Portland limestone cement (PLC) replacing with different percentages, viz. 0, 5, 10, 15, 20, 25 and 30% in ordinary Portland cement (OPC). OPC clinkers with three different qualities of limestone are interground to develop different types of PLC-based cements. From the experimental results, it is inferred that an appropriate choice of clinker quality, limestone quality and percentage of limestone can lead to production of limestone cement with desired properties. Based on the strength and interaction factor values, it can be concluded that optimum replacement (15%) of low-grade limestone could satisfy the performance, similar to an OPC 43 grade cement.