Experimental Investigations on the On-Site Crack Control of Pier Concrete in High-Altitude Environments

Abstract

Concrete structures in high-altitude environments face many challenges. Establishing concrete crack control methods in high-altitude environments is crucial for enhancing the service capacity of concrete structures. In this study, a multi-field (hydration-temperature–humidity-constraint) coupling model was used to quantitatively assess the cracking risk of pier bodies at high altitude. On-site crack control tests were conducted on pier bodies using a micro-expansion anti-cracking agent to demonstrate the effectiveness of deformation shrinkage compensation in crack control at high altitudes. The results indicated that there was a risk of cracking in the pier body at high-altitude conditions, especially within 0.3 m from the pile cap and ±2.5 m from the center of the pier side surface. Compared with conventional piers, the micro-expansion anti-cracking agent approximately doubled the unit expansion deflection of piers at high temperatures while reducing the unit shrinkage deflection of piers by 11% to 12% at low temperatures. The concrete in conventional pier bodies was in a tension state after long-term hardening, while the concrete treated with the micro-expansive anti-cracking agent was in compression. Therefore, the deformation compensation effect of the micro-expansive anti-cracking agent was significant and reduced the risk of concrete cracking. In addition, early freezing had a significant impact on concrete strength, underscoring the importance of effective temperature control during the early stages of concrete placement in high-altitude environments.

Keywords

• high altitude
• concrete
• on-site tests
• strain compensation
• cracking control