减缩剂和膨胀剂对水泥基自流平砂浆收缩开裂性能的影响比较研究

Influence of Shrinkage Reducing Agent and Expansion Agent on the Shrinkage Cracking of Cementitious Self-leveling Mortar

研究了减缩剂和膨胀剂对水泥基自流平砂浆的自收缩、干燥收缩的影响以及减缩剂对塑性开裂性能的影响,同时对作用机理进行了分析。试验结果表明,减缩剂和膨胀剂对自流平砂浆的自收缩、干燥收缩有显著的抑制作用。掺2%的减缩剂28d自收缩率和干燥收缩率分别降低了83.7%和49%;膨胀剂掺量达到12%时,28d自收缩率降低了62.8%,干燥收缩率降低了39.8%;减缩剂对塑性收缩开裂的抑制作用明显,掺量为2.0%时,开裂指数为0。

The shrinkage and shrinkage cracking is very important for cementitious self-leveling mortar. The influence of shrinkage reducing agent and expansion agent on the autogenous shrinkage,drying shrinkage of cementitious self-leveling mortar and the influence of shrinkage reducing agent on the plastic cracking were investigated,and the analysis were done under the action mechanism of shrinkage reducing agent and expansion agent to cementitious self-leveling mortar. The experimental results show that the shrinkage reducing agent and expansion agent can notablely restrain both the autogenous shrinkage and drying shrinkage of self-leveling mortar. When the amount of shrinkage reducing agent is 2% ,the autogenous shrinkage of self-leveling mortar at 28d is reduced 83.7% and the drying shrinkage at 28d is reduced 49% ;When the amount of expansion agent is up to 12% ,the autogenous shrinkage of self-leveling mortar at 28d is reduced 63.7 % and the drying shrinkage at 28d is reduced 39.8 % ; the reduction of shrinkage reducing agent to plastic shrinkage cracking is in evidence, when the amount is 2.0% ,the crack index is 0.