<p>This study investigates the durability properties of Ordinary Portland Cement (OPC) and LC³-50 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 (LWA) (0% and 100%) were investigated in OPC and LC³-50 concretes, which showed that the use of 100% lightweight in OPC and LC³-50-based concretes reduced compressive strength and splitting tensile strength by 60–65% and 25–30% in comparison to natural coarse aggregates without exposure to CO₂. The reduction in the compressive and splitting tensile strengths due to CO₂ exposure was more OPC than LC³-50 concrete due to dense microstructure, which is also evident by the permeability results. The effect of CO₂ in reducing compressive and splitting tensile strengths at later ages (i.e. 270 and 365&#xa0;days) becomes less than 90 and 180&#xa0;days. The pull-out strength of OPC and LC³-50 concretes is almost similar at 7 and 28&#xa0;days; however, the 28-day pull-out strength was observed to be 3 times higher than 7&#xa0;days. Similarly, the permeability of LC³-50 concrete is better than OPC. Therefore, it can be concluded that LC³-50 in concrete improves durability and can be suitably used with 100% lightweight. Similarly, the permeability of LC³-50 concrete is better than OPC. The OPC specimens show 70% higher permeability and greater sorptivity than LC³-50. Using 100% lightweight aggregates reduces permeability by 50%, and lightweight concrete with OPC has a 21% higher absorption rate than LC³-50. Therefore, it can be concluded that LC³-50 in concrete improves durability and can be suitably used with 100% lightweight.</p> Graphical Abstract <p></p>