Study on the Properties of Shrinkage Cracking of Concrete Containing Various Mineral Admixtures Assumed on Site

通过抗压强度试验、预埋钢筋试验、自生收缩试验和干缩试验，研究了高炉渣和/或粉煤灰混凝土在28d强度相同的情况下的开裂行为。结果表明，外加剂对混凝土的自生收缩应变和干缩应变影响不大。与普通混凝土相比，掺高炉渣混凝土的开裂时间要早于普通混凝土，而掺高炉渣混凝土的开裂时间与普通混凝土相差不大。此外，无论掺入外加剂，混凝土开裂时的约束应力与劈裂抗拉强度之比为0.6~0.7。

The purpose of this study is to clarify the cracking behavior of concrete containing blast furnace slag and/or fly ash in case of same strength at 28 days through the compressive strength test, the embedded reinforcing bar test, the autogeneous shrinkage test and the drying shrinkage test.As a results showed that the influence of admixtures on the autogeneous and drying shrinkage strain of concretes is small. And concrete with blast furnace slag cracked at earlier ages than plain concrete, in spite of concrete with fly ash cracked at the same age. Furthermore, the ratio of restrained stress to splitting tensile strength of concrete at the cracking was 0.6 to 0.7 regardless of containing admixtures.