不同类型减缩剂减缩效果比较分析

发布时间：2018-05-31 06:23

本文选题：高水胶比 + 内养护　；参考：《建筑材料学报》2016年01期

【摘要】：在高水胶比混凝土中掺加不同类型减缩剂(内养护剂(SAP)、膨胀剂及有机减缩剂),然后研究不同类型减缩剂对混凝土抗压强度、化学收缩、自收缩、干燥收缩、塑性开裂的影响,对比分析不同类型减缩剂在不同混凝土养护条件下的减缩效果.结果表明:SAP、膨胀剂、有机减缩剂对混凝土3d抗压强度均有不同程度的负面影响,其中有机减缩剂负面影响最大,但SAP可促进混凝土28d抗压强度增长;SAP对混凝土化学收缩、自收缩、干燥收缩及塑性开裂均具有较好改善效果,这缘自于SAP对混凝土内部相对湿度的调控作用;膨胀剂对混凝土养护条件要求苛刻,在密封条件下膨胀剂具有较好的补偿自收缩作用,但在干燥养护条件下膨胀剂补偿干燥收缩的效果并不理想;有机减缩剂对密封条件下混凝土自收缩的补偿效果不如SAP及膨胀剂,但在干燥条件下其具有良好的补偿混凝土干燥收缩的效果,这是因其能降低混凝土溶液表面张力和内部水分蒸发速率的缘故.
[Abstract]:In high water-binder ratio concrete, different types of shrinkage reducers (internal curing agent, expansion agent and organic shrinkage reducer) are added into concrete. Then the effects of different types of shrinkage reducers on compressive strength, chemical shrinkage, autogenous shrinkage, drying shrinkage and plastic cracking of concrete are studied. Contrastive analysis of shrinkage reduction effects of different types of shrinkage reducers under different curing conditions of concrete. The results show that SAP can increase the compressive strength of concrete in 28 days and the chemical shrinkage of concrete can be improved by SAP. The results show that there are some negative effects on the compressive strength of concrete in different degree, among which the organic reducing agent has the most negative effect on the compressive strength of concrete in three days. Autogenous shrinkage, dry shrinkage and plastic cracking all have better effect, which is due to the effect of SAP on regulating the relative humidity of concrete, and the expansion agent is demanding on the curing conditions of concrete. The expansion agent can compensate for the autogenous shrinkage under the condition of sealing, but the effect of the expansion agent on compensating the drying shrinkage under the condition of drying and curing is not ideal. The effect of organic shrinkage reducer on the self-shrinkage of concrete under sealing condition is not as good as that of SAP and expansion agent, but it has a good effect on compensating the drying shrinkage of concrete under dry conditions. This is because it can reduce the surface tension of concrete solution and internal moisture evaporation rate.
【作者单位】：武汉理工大学硅酸盐建筑材料国家重点实验室;华新混凝土骨料事业部技术中心;
【基金】：国家自然科学基金资助项目(51172173)
【分类号】：TU528.042

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