Shear design and life cycle assessment of novel limestone calcined clay cement reinforced concrete beams

To reduce the impact on global warming, many countries and regions are advocating the use of low-carbon and green supplementary cementitious materials (SCMs) to improve the cement industry. This study investigates the shear behavior of reinforced concrete (RC) beams made with a novel green concrete, limestone, calcined clay, and cement clinker (LC3). Full-scale shear tests were conducted on RC and LC3-RC beams to evaluate their fundamental behavior for structural applications. The shear resistance of LC3 concrete beams was evaluated using Chinese, American, and Eurocode codes, while carbon emission and environmental impact were analyzed by life cycle assessment (LCA). Results showed that LC3-RC and RC beams exhibited similar shear behavior in terms of crack initiation, propagation, and development. The increase in concrete strength improved the stiffness of LC3-RC specimens, while RC specimens remained unchanged. The ductility of RC specimens was inversely proportional to concrete strength, while LC3-RC beams exhibited optimal ductility. The increase in stirrup ratio significantly improved the shear resistance of both LC3-RC and RC beams. With increased shear-span ratio, the failure mode of LC3 specimens improved, changing from diagonal-compression to shear compression or diagonal tension failure. The shear resistance of both LC3-RC and RC beams was underestimated by GB 50010-2010, ACI 318-19, and Eurocode 2. LC3 concrete significantly reduced energy consumption and carbon emissions and achieved favorable environmental benefits in terms of GWP, PMFP, POFP, TAP, and TETP. Increasing usage of limestone in LC3 may further decrease environmental potential without sacrificing mechanical properties. The findings of this study contribute to the development of sustainable and environmentally friendly structures in engineering.