Influence of Combined Hauling Time and Temperature on Flow Properties of Self-Consolidating Concrete:Retempering Remediation

摘要

This investigation studied the retempering technique of remediation to mitigate the influence of combined transportation time and extreme hot and cold temperatures on plastic self-consolidating concrete (SCC). This method of remediation consisted of adjusting admixture dosage at the end of hauling to produce a matrix with similar fresh properties as those of the control concrete prepared at the temperature of 21℃ and transportation duration of 10 minutes. Seven different temperatures (43, 36, 28, 21, 14, 7, and - 0.5℃) and five different hauling times (10, 20, 40, 60, and 80 minutes) were adopted. Polycarboxylate-based high-range water-reducing admixture (HRWRA) and viscosity-modifying admixture (VMA) were used to produce the selected matrices with slump flow of 635 ± 25 mm or 711 ± 25 mm, visual stability index (VSI) of 0 (highly stable concrete) and T_(50) of 2 to 5 s. Laboratory test results revealed that the retempering method of remediation was successful in mitigating the adverse effect of combined hauling time and temperature on the flow characteristics of self-consolidating concrete.