Study on mechanical properties and microstructure of green ultra-high performance concrete prepared by recycling waste glass powder

Ultra-high performance concrete (UHPC) encounters hindrance in pursing carbon neutrality and extended applications due to the dosage of cementitious materials and high energy consumption. To address this problem, this study utilized WGP to replace placement in the production of UHPC-WGP and invested its impact on workability, mechanical properties, and microstructure. The research results showed that incorporating WGP improved the flowability of UHPC and reduced its early-age mechanical properties but significantly enhanced the later-age mechanical properties. When the WGP content is 20 %, the sample's compressive strength after 28 days increases by 8.6 %. The specimens with 28 days exhibited the highest flexural strength and ultimate deflection, reaching 24.8 MPa and 0.809 mm, respectively, and the UHPC specimens (90 d) demonstrated the lowest total porosity, reduced by 14.6 % compared to the reference group. Furthermore, scanning electron microscopy (SEM) observations revealed that WGP had a good micro-aggregate filling effect and pozzolanic effect improved the microstructure. Finally, low cost and energy consumption characteristics further promote the sustainable application of WGP-based UHPC.