2025 Volume 23 Issue 1 Pages 1-21
As an advanced cement-based composite material, ultra-high performance concrete (UHPC) exhibits outstanding properties. However, the scope and scale of UHPC applications are limited by several issues, such as high hydration temperature rise, insufficient elastic modulus, high autogenous shrinkage (AS), and high cost. Incorporating coarse aggregate (CA) can partially overcome the limitations of traditional UHPC. The characterization of the properties, AS, and cracking risk at an early age is important for the design and application of UHPC with CA (CA-UHPC). The temperature stress test machine (TSTM) was employed to analyze the impact of CA content on the early-age temperature evolution, AS, and cracking risk of CA-UHPC under uniaxial restrained condition. The correlation between the performance of CA-UHPC and its microstructure was analyzed through the image analysis and Scanning Electron Microscope (SEM) test. Experimental results demonstrated that the AS and cracking risk of CA-UHPC decreased with an increase in the CA content. A modified model was proposed to predict the AS of CA-UHPC, considering the impact of CA content. Two critical parameters were utilized to evaluate the cost-performance ratio of CA-UHPC comprehensively. Considering the properties, AS, cracking risk, and cost-performance ratio, the optimal CA content for CA-UHPC was 400 kg/m3.
