A study of pore structure in aggregate which cause concrete shrinkage

用压汞法和气体吸附法测定了骨料的孔结构。在MIP测试中，检测到直径大于10 nm的孔结构。在气体吸附实验中，检测到孔径小于10 nm的微孔结构。研究发现，收缩骨料中含有大量的小孔结构，具有较大的比表面积。通过MIP测试发现，两种材料的大孔结构没有差异。这说明用吸水率试验难以鉴别集料是否收缩。

Pore structure in aggregate was measured by Mercury Intrusion Porosimetery (MIP) test and Gas adsorption test. In MIP test, pore structure which diameter is over 10 nm was detected. And in Gas adsorption test, pore structure which diameter is under 10 nm was detected. In this research, it was found that shrinkable aggregate contains a lot of small pore structure which is large surface area. And it was found that there is no difference in large pore structure which was detected by MIP test. This result indicated that it was difficult to identify aggregate is shrinkable or not by water adsorption test.