Durability Performance of Opc and Lc 3 -50 Concrete Containing Lightweight Aggregates

This study investigates the durability properties of OPC and LC ³ -50 concretes containing shale as lightweight coarse aggregates acquired from the Balochistan Province of Pakistan for structural concrete in comparison to natural coarse aggregates. The physical properties of shale aggregates were initially assessed by performing crushing value, absorption, Impact value tests and specific gravity. In this study, two replacements for lightweight aggregate (0% and 100%) were investigated in OPC and LC ³ -50 concretes, which showed that the use of 100% lightweight in OPC and LC ³ -50-based concretes reduced compressive strength and splitting tensile strength by 60–65% and 25–30% in comparison to natural coarse aggregates without exposure to CO ₂ . The reduction in the compressive and splitting tensile strengths due to CO ₂ exposure was more OPC than LC ³ -50 concrete due to dense microstructure, which is also evident by the permeability results. The effect of CO ₂ in reducing compressive and splitting tensile strengths at later ages (i.e. 270 and 365 days) becomes less than 90 and 180 days. The pull-out strength of OPC and LC ³ -50 concretes is almost similar at 7 and 28 days; however, the 28-day pull-out strength was observed to be 3 times higher than 7 days. Similarly, the permeability of LC ³ -50 concrete is better than OPC. Therefore, it can be concluded that LC ³ -50 in concrete improves durability and can be suitably used with 100% lightweight.