预吸水SAP对高强混凝土毛细管负压和塑性开裂的影响

Effect of pre-watered SAP on the capillary pressure and the plastic-shrinkage cracking of high-strength concrete

通过混凝土内部毛细管负压试验以及混凝土抗裂性能试验,研究分析预吸水SAP对高强混凝土塑性开裂的影响。试验结果表明:混凝土塑性阶段初始裂缝出现时间与混凝土毛细管负压曲线的拐点出现时间成正比;塑性阶段裂缝数量、裂缝面积与毛细管负压增长坡度成反比。SAP额外引水量比越大,混凝土毛细管负压拐点出现时间越迟,毛细管负压增长坡度越平缓,混凝土塑性阶段抗裂性能越好。

The effect of pre-watered SAP on the plastic-shrinkage cracking of high-strength concrete is studied by the capillary pressure test and cracking resistance test of concrete. The results show the time of the first plastic-shrinkage cracking is pro-portional to the time of turning point of capillary pressure;the number and area of cracks are inversely proportional to the growth slope of capillary pressure. The larger additional water diversion ratio of SAP,the later the occurrence of capillary pressure inflection point,the gentler the capillary pressure increase slope,and the better the crack resistance of concrete in plastic stage.