自密实混凝土的收缩性能研究

为研究不同复合膨胀剂掺量对自密实混凝土收缩性能的影响，通过优化配合比，获得两种不同复合膨胀剂掺量的自密实混凝土，并以普通混凝土为基准，分别将其拌和物工作性、限制膨胀率、抗压强度、早龄期自收缩性能和体积稳定性进行对比分析。研究结果表明:复合膨胀剂能有效改善拌和物离析性能；基准混凝土成型后均表现为收缩状态，而自密实混凝土的体积先微膨胀后自收缩，且收缩变化并不明显；干燥失水条件下，基准混凝土随着龄期的增加，体积稳定性一直呈收缩变化，而自密实混凝土的体积收缩率呈先涨后缩变化，及时、充分对自密实混凝土进行保湿养护，

Study on Shrinkage Performance of Self-compacting Concrete

In order to study the effect of different compound expansion agent content on shrinkage performance of self compacting concrete, the mixture proportion is optimized to obtain two kinds of self compacting concrete with different compound expansive agent content, the workability, restricted expansion rate and compressive strength, early age autogenous shrinkage performance and volume stability were respectively compared and analyzed with ordinary concrete as a benchmark. The research results show that:the composite expansive agent can effectively improve the performance of mixture segregation; the reference concrete shrinks after setting, and self compacting concrete expands and then slightly shrinks; under drying and water loss conditions, with the increase in the setting period of the reference concrete, its volume stability shrinks while the volume shrinkage of self compacting concrete is firstly increased and then reduced to timely and fully wet and cure self compacting concrete, and so shrinkage compensation performance can be effectively improved.