水泥石的结构、组成与干缩性能的关系

Relationship Between the Microstructure, Composition and Drying Shrinkage of Cement Pastes

通过干缩测定、IR分析、TG-DSC综合热分析、孔结构测定(MIP法)等方法研究了水泥石的结构、组成与干缩性能的关系。水泥石的结构、组成(孔结构、水化产物的组成和数量、C-S-H的表面性能及化学结构)的改变通过采用矿物掺合料等量取代水泥、干燥前养护温度改变(20℃和60℃)来实现。结果表明,可逆收缩取决于水化产物的数量与C-S-H凝胶的表面性能与化学结构,随压汞法测得的小于30nm的孔体积增加而线性增加;不可逆收缩则与C-S-H凝胶的化学结构及其表面性能有关,C-S-H凝胶的聚合度增加,表面积下降,不可逆收缩减小;总干缩中部分不可逆收缩是由C-S-H的硅酸盐聚合度增加而造成的。

The relationship between the microstructure, composition and drying shrinkage of cement pastes was studied by measuring of drying shrinkage （including reversible portion and irreversible portion）, pore structure and pore size distribution of hydrated cement mortars, and by using IR and TG-DSC analysis. The microstructure and composition of cement pastes were manipulated by mineral additives and curing temperature. The results show that the reversible drying shrinkage is dependent on the quantity, surface area and chemical structure of calcium silicate hydrate （C-S-H）, and increases linearly with small pore volume as measured by mercury intrusion porosimetry （≤30 nm pore diameter） ， And the irreversible portion is mainlv affected by the chemical structure and surface area of C-S-H, and it will decrease with the increase in the degree of silicate polymerization and decrease in the surface area of C-S-H. Irreversible drying shrinkage is partiallv caused bv the increase in the degree of silicate polymerization of C-S-H.