内养护剂对自密实混凝土性能的影响

Effeet of internal curing agent on the performance of self-compacting concrete

尝试采用新型聚合物内养护方法抑制早期收缩,研究了内养护剂吸水倍率、掺量对自密实混凝土工作性、力学性能、体积稳定性的影响.结果表明:内养护剂1∶7引水时,自密实混凝土坍落度损失较大.当内养护剂1∶14引水时,随着内养护剂掺量由2%增加到4%,强度先增大后减小.当掺量由2%增加到4%时,自密实混凝土7 d自收缩分别下降25.2%、35.8%、58.3%,说明提高内养护剂掺量抑制自收缩效果显著.掺内养护剂组90 d电通量均低于空白组,说明内养护剂的加入能够有效改善自密实混凝土抗氯离子渗透性.掺入内养护剂后,15 min和38 h以前的胶凝浆体水化反应变慢,加速期延迟,说明内养护剂延缓了凝胶浆体的水化反应.内养护剂在不明显降低强度的前提下有效抑制了自密实混凝土的早期自收缩。

It attempts to use a new polymer internal curing method to inhibit early shrinkage,and studies the effect of water absorption rate and content of internal curing agent on the workability,mechanical properties and volume stability of SCC.The results show that the slump loss of SCC is greater when the internal curing agent is diverted at 1∶7.When the internal curing agent was introduced at 1∶14,as the content of the internal curing agent increased from 2%to 4%,the strength increased first and then decreased.When the content was increased from 2%to 4%,the self-condensation of SCC at 7 days decreased by 25.2%,35.8%,and 58.3%,indicating that the effect of increasing the amount of internal curing agent on inhibiting self-contraction was significant.The 90 d electric flux of the internal curing agent group was lower than that of the blank group,indicating that the addition of the internal curing agent can effectively improve the resistance to chloride ion penetration of the SCC.After the internal curing agent was added,the hydration reaction of the gel slurry before 15 min and 38 h became slower and the acceleration period was delayed,indicating that the internal curing agent delayed the hydration reaction of the gel slurry.The internal curing agent effectively inhibits the early self-shrinkage of SCC without significantly reducing the strength.