Time-dependent rheological analysis of self-consolidating concrete mixtures considering various mixing temperatures

Abstract

This study aims to investigate the effect of the temperature of the self-consolidating concrete (SCC) mixture during casting on fresh and hardened properties for two types of SCC. Also, the rheological properties of the mixtures were assessed at specific time intervals (0, 20 and 40 min after mixing) to determine their sensitivity to changes in mixtures’ properties and temperature over time. For this purpose, two categories of SCC were prepared: Powder type and Viscosity-Agent type. Silica fume, metakaolin (MK) and slag were utilised as substitutes for cement in these samples. The mixtures were tested at low and high temperatures of 5 °C and 34 °C, respectively, with an average temperature of 21 °C. Results indicated that as the mixture temperature decreased, the yield stress decreased by 30% and the plastic viscosity increased by 25% on average. Conversely, as the temperature increased, the yield stress increased by 20% and the plastic viscosity decreased by 40% on average. Moreover, increasing the mixture temperature resulted in a 10% increase in the 7-d compressive strength but a 15% decrease in the 28-d compressive strength of the specimens. Additionally, increasing the rest time after mixing increased the yield stress, while the plastic viscosity remained relatively stable with occasional increases.