Influence of colloidal nanosilica on hydration kinetics and properties of CaO/CaSO_(4)-activated slag binder  

作　　者：Qing Liu Qingming He Ruoyun Li Yanfei Feng Xianjun Lyu Junxiang Wang Lin Li 

机构地区：[1]College of Chemical and Biological Engineering,Shandong University of Science and Technology,Qingdao 266590,China [2]Moutai Institute,Huairen 564507,China

出　　处：《International Journal of Mining Science and Technology》2022年第6期1407-1418,共12页矿业科学技术学报（英文版）

基　　金：supported by Natural Science Foundation of Shandong Province(No.ZR2019BEE075);Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(No.2019RCJJ007);Young Science and Technology Innovation Program of Shandong Province(No.2020KJD001);Youth Science and Technology Talent Growth Program of Guizhou Province(No.KY[2018]466).

摘　　要：To solve the energy consumption and CO_(2) emission during cement production,the new binders must be developed as an alternative to cement.CaO/CaSO_(4)-activated slag binder is an eco-friendly and safe cementitious material;however,its low strength during initial stages limits its applications.In this study,colloidal nanosilica(CNS)was employed as an additive to improve the strength of CaO/CaSO_(4)-activated slag binder,and the effects of CNS on the workability,hydration kinetics,hydration products(type,quantity,and polymerization degree),and binder microstructure were thoroughly investigated.A moderate CNS content,through its nucleation effect,significantly increased the hydration rate of the nucleation and crystal growth(NG),phase boundary interaction(I)and diffusion(D)processes,which generated large quantities of calcium aluminosilicate hydrate(C-A-S-H)gel in the initial hydration stage.Meanwhile,the addition of CNS improved the polymerization degree of C-A-S-H gel.This amorphous reactant well-filled the pore space between slag particles and yielded a compact microstructure,consequently enhancing the binder strength.Considering the reduction in fluidity and the increase in production cost,the CNS mass fraction was controlled as3%,and the binder reached the satisfactory strengths of 3.87,24.47,31.43,and 41.78 MPa at 1,3,7,and 28 d,respectively.

关 键 词：Alkali-activated slag Colloidal nanosilica Strength Hydration kinetics C-A-S-H gel 

分 类 号：TQ172.4[化学工程—水泥工业]