矿渣-水泥硬化浆体水化产物结构研究

Study on structure of the hydrated product of slag-cement hardened paste

采用XRD、^(29)Si NMR、纳米压痕以及SEM分析等方法对矿渣-水泥体系的水化产物结构进行研究,结果表明,随着水化龄期的延长,矿渣-水泥体系中的Ca(OH)_2含量呈现先增加后减少的趋势,7 d时Ca(OH)_2含量达到最大,水化14 d后,Ca(OH)_2含量逐渐减少;矿渣-水泥水化浆体中的硅氧四面体结构主要以Q^0、Q^1和Q^2状态存在;部分Al^(3+)取代硅氧四面体中的Si^(4+),生成含Al的C-A-S-H凝胶;矿渣-水泥体系水化3 d时,水化产物主要以LD C-S-H为主,水化28 d后,主要以HD C-S-H以及C-S-H/CH的混合相为主;与纯水泥相比,矿渣-水泥体系中HD C-S-H含量提高,孔隙率降低,结构更为致密。

In this paper,XRD,29Si NMR,nanoindentation and SEM were used to study the hydration product structure of the slag-cement paste.The results show that with the extend of cement hydration age,the content of Ca(OH)2 in the slag-cement paste increased firstly and then decreased,and reached the maximum at 7d.After 14 days of hydration,the content of Ca(OH)2 decreased gradually.The silica tetrahedron structure in the slag-cement paste was mainly in the state of Q^0,Q^1 and Q^2,partial Al3+ replaces the Si^4+ within the silica tetrahedron produces a calcium aluminosilicate hydrate(C-A-S-H)gel.When the slag-cement hydrated for 3d,the products are mainly LD C-S-H.After hydration for 28days,the main components are HD C-S-H and C-S-H/CH mixed phases.Compared with the pure cement paste,in the slag-cement paste,the HD C-S-H content increases,porosity decreases,and the structure becomes more compact.