تاثير درجة حرارة ماء الخلط علي خواص الخرسانة الطازجة والمتصادة

Abstract

. This research aims to study the effect of mixing water temperature on the properties of fresh and hardened concrete according to British Standard specifications. The study was conducted by fixing the temperatures of solid materials (aggregate, cement, sand) at approximately constant values, and changing the mixing water temperature to five different degrees: 10, 20, 30, 40, 50°C. The mix with water temperature of 20°C was adopted as a reference mix for comparison. The fresh concrete temperature was measured immediately after mixing, the slump test was performed, then standard test cubes were cast and tested after 7 and 28 days to determine compressive strength . The results showed that the fresh concrete temperature increases with increasing water temperature, but the increase is less than the increase in water temperature due to the effect of solid materials. It was also found that workability (slump) decreases with increasing temperature. Regarding compressive strength, the best results were at 30°C, recording the highest strength after 28 days (31.05 N/mm²), while the lowest strength was at 50°C (27.90 N/mm²). The study recommended controlling mixing water temperature within the range of 20-30°C to obtain the best concrete properties Keywords: Concrete, mixing water temperature, compressive strength, workability, hot weather, British Standard, reference mi