养护温度对高延性水泥基材料力学性能的影响

摘要

The effects of different curing temperatures on the mechanical properties of engineered cementitious composites (ECC) is investigated by employing the four-point bending test, compressive strength and flexural strength. Four different curing temperatures, which are 20, 40, 60 and 80 ℃, are applied to the specimens. The results indicate that the early age deflection of ECCs decreases gradually as curing temperature increases. The deflection and toughness index of ECC show no significant change as the curing temperature is above 40 ℃.Compressive strength and flexural strength at early age increase notably as the curing temperature is higher.However, the curing age has few effect on the compressive strength and flexural strength of ECC specimens at high curing temperature. Compared to the specimens at other curing temperarures, the cracks of ECCs cured at room temperature is much finer. The toughness of ECC with 80％ fly ash is improved when the curing temperature is 60 ℃, and the compressive strength can reach to 70 MPa.%研究养护温度对高延性水泥基复合材料性能的影响,分析养护温度在20、40、60和80 ℃时水泥基复合材料的抗弯性能、抗压强度、抗折强度及裂缝分布特点.结果表明,养护温度越高,高延性水泥基复合材料的早期跨中挠度越小;养护温度高于40 ℃时,试件的跨中挠度和韧性指数随龄期延长无明显变化;高养护温度能显著提高高延性水泥基复合材料的早期抗压强度和抗折强度,龄期对高温养护条件下高延性水泥基复合材料的抗压、抗折强度影响不大;粉煤灰掺量相同时,常温养护下高延性水泥基复合材料的裂缝更加细密均匀;养护温度为60 ℃时,粉煤灰掺量提高至80%,高延性水泥基复合材料的韧性显著提高,28 d抗压强度可达70 Mpa.