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BULLETIN OF THE CHINESE CERAMIC SOCIETY ›› 2021, Vol. 40 ›› Issue (2): 384-391.

Special Issue: 水泥混凝土

• Cement and Concrete • Previous Articles     Next Articles

Property and Pore Structure of Nano-SiO2 Modified High Volume Slag Powder-Cement Cementitious System

LIN Peitong1, ZENG Yu1, ZHAO Yonggang1, LIU Jinhong2, WANG Junfeng1,3, LU Liulei1   

  1. 1. College of Civil Engineering and Architecture, Hainan University, Haikou 570228, China;
    2. 91053 Force, Beijing 100000, China;
    3. Foshan GENAITE New Building Material Technology Co., Ltd., Foshan 528000, China
  • Received:2020-09-09 Revised:2020-11-06 Online:2021-02-15 Published:2021-03-10

Abstract: Using the strong pozzolanic activity of precipitation method nano-silica (PNS) to improve the early compressive strength and loose internal structure of the high volume slag powder-cement cementitious system. The influence of PNS on the compressive strength and the resistance to chloride ion permeability of high volume slag powder-cement cementing system were studied. The hydration products and pore structure of the system were analysed by XRD, TG-DSC and MIP. Research shows that with the increase of PNS content, the compressive strength of the specimens increases, especially the 7 d compressive strength. The strength of specimens with 5% (mass fraction, the same blow) PNS increases by 20%. The resistance to chlcride ion penetration capacity first increases and then decreaces. When PNS content is 3%, it reaches the optimal level, and its 28 d chloride ion diffusion coefficient is 44.8% lower than that without PNS. PNS can consume a large amount of Ca(OH)2 in the early stage and generate more hydration products such as C-S-H gel, which makes the pore structure more compact and reduces the porosity. Incorporating PNS within the range also refines the pore size.

Key words: nano-SiO2, high volume slag powder, resistance to chloride ion penetration, pore structure, compressive strength

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