Influence of Mixture Compositions on Impact Resistance and Mechanical Properties of Concrete Cured in Cold Temperature Conditions

This study aimed to present the effect of mixture proportions (including coarse-to-fine aggregate ratio and water-to-binder ratio) and mixture compositions (including the addition of different supplementary cementing materials and fibers) on the impact resistance and mechanical properties of concrete cured in cold temperatures. The impact resistance was evaluated using drop-weight and flexural impact tests conducted on concrete samples cured in different curing conditions. The studied parameters included coarse-to-fine aggregate (C/F) ratio (0.7 and 1.2), water-to-binder (w/b) ratio (0.4 and 0.55), type of supplementary cementing materials (SCMs) [20% metakaolin (MK) and 10% silica fume (SLF)], and the addition of steel fibers (0.35%) (SFs). The studied mixtures were cured under different curing conditions, including moisture condition at 23°C, air condition at 23°C, +5°C curing condition, and −10°C curing condition. The positive effect of using SFs and SCMs (MK and SLF) on enhancing the impact resistance and splitting tensile strength (STS) was more pronounced in samples cured at normal curing temperatures compared to samples cured at low temperatures. The mechanical properties and impact resistance of mixtures developed with higher C/F and w/b ratios were more affected by the low-temperature curing condition compared to the control mixture (with lower C/F and w/b ratios). The results also showed that low-temperature curing had a more pronounced negative effect on the impact resistance and STS than the compressive strength.