Hydration and Microstructure of Steel Slag as Cementitious Material and Fine Aggregate in Mortar

Molecules

Ping Duan¹  Jinping Jiang¹  Wu Jing²  Sha Ding³ 

[1] Key Laboratory of Geological Survey and Evaluation of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China;School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China;Wuhan Hanyang Municipal Construction Group Co., Ltd., Wuhan 430050, China;

关键词: steel slag;    fine aggregate;    cementitious material;    hydration;   

DOI  :  10.3390/molecules25194456

来源: DOAJ

【 摘 要 】

Due to the low hydration activity and poor volume stability, extensive steel slag utilization is restricted. In this paper, the hydration process and microstructure of alkali-activated materials with steel slag as a cementitious material and fine aggregate were studied. The phase composition and micro-morphology of hydration products were measured using XRD, NMR and SEM. The response relationship between microstructure and mechanical properties during hydration was revealed. The results show that the main hydration products of the alkali-activated steel slag powder-granulated blast furnace slag powder cementitious system are Ca(OH)₂ and calcium aluminosilicate hydrate (C-A-S-H) gel. With the progress of hydration, the amount of calcium silicate hydrate (C-S-H) gel and the average molecular chain length increase, Al[4]/Si decreases, while C/S increases first and then decreases, and the structure of cement paste becomes much more compact. The interface between steel slag sand and cement paste is denser than that of river sand, since the hydration occurs on the surface of steel slag sand, which leads to the formation of C-A-S-H gel and Ca(OH)₂. As a result, the compressive strength of concrete prepared by steel slag sand is higher than that of river sand with the same mix proportion.

【 授权许可】

Unknown