Abstract: 200 million tons of coal fly ash waste are deposited annually in China, which poses a severe environmental threat. Hence, a sustainable fly ash-based lightweight aggregate (FA-LWA) with a core-shell structure was developed to produce lightweight concrete (LWC) structures. This study investigated the shear performance of FA-LWC structures. The experimental results show that compared to shale-based LWC, FA-LWC exhibited increases in cracking strength (+31.6%), fracture energy (+18.9%), and shear strength (+27.4%). In addition, the experimental results demonstrate that incorporating 1.0vol% glass fibers (GFs) into LWC beams leads to a 7.4% improvement in the cracking load, a 33.6% enhancement in fracture energy, and a substantial 41.0% increase in shear strength, highlighting the significant role of GFs in improving the shear performance of LWC beams. Among the five selected international standards, Eurocode 2 (EN 1992-1-1) and CEB-FIP-2022 provided a more accurate prediction for the shear strength of LWC beams prepared with FA-LWC. This study addresses the current lack of experimental data on the shear performance of cold-bonded FA-LWA concrete structures, offering new insights into their failure modes and design implications.
