SAP对高水胶比混凝土塑性开裂的影响

Effects of SAP on the Plastic Shrinkage Cracking of Concrete of High Water-Binder Ratio

针对高水胶比混凝土早期开裂严重影响混凝土耐久性能的问题,研究了掺量(质量分数)为0.2%,0.3%和0.4%的高吸水性树脂(SAP)对高水胶比(质量比0.5)混凝土特定状态下的早期抗裂性能、力学性能和体积稳定性能的影响,并结合水分蒸发试验,研究了掺入SAP后混凝土的失水规律.结果表明:掺入SAP后,可显著提高高水胶比混凝土的早期抗裂性能,SAP掺量为0.2%,0.3%和0.4%的混凝土早期开裂面积分别降低了81%,88%和98%,SAP的掺入能够明显减缓混凝土的水分挥发,抑制其体积收缩,并且不会对混凝土的力学强度造成较大的负面影响.

Early age cracking of high water-binder ratio concrete seriously affected the durability of con- crete. The effects of super absorbent polymer（SAP） particles（mass fractions are 0.2% ,0. 30%,0.40%） on the early cracking resistance, mechanical properties and volume stability of concrete of high water-binder ratio（mw/mB =0. 5） were investigated. Water losing regularity of concrete was also studied by using evap- oration experiment. The results show that SAP can effectively improve the early cracking resistance of the high water-binder ratio concrete. When the mass fraction of SAP were 0.2 %, 0.3% and 0.4 %, the areas of early age cracking of concrete are reduced by 81%, 88% and 98% respectively. Addition of SAP can significantly reduce water evaporation of concrete, inhibit its volume shrinkage, and does not decrease its mechanical strength.