无机盐对水泥石水化程度和孔结构的影响(英文)

EFFECT OF INORGANIC SALTS ON DEGREE OF HYDRATION AND PORE STRUCTURE OF CEMENT PASTES

采用压汞法研究了水灰比为0.3和0.5的掺加无机盐外加剂[CaCl2,Na2SO4,NaNO2和Ca(NO3)2]水泥石在3d和28d时的孔结构,并测试化学结合水含量。结果表明:CaCl2,Na2SO4和NaNO2能促进水泥水化;CaCl2促进水泥水化作用最为明显,并可降低水泥石大孔和毛细孔孔隙率;Na2SO4增大了大孔孔隙率;NaNO2能显著减小28d时毛细孔连通孔径和毛细孔孔隙率;Ca(NO3)2在前3d对水泥水化没有明显的作用,在3d时水泥石中大孔和毛细孔孔隙率以及毛细孔连通孔径增大。

The pore structures of cement paste with a water-cement ratio of 0.3 and 0.5 in mass, containing inorganic salts admixture （CaCl2, Na2SO4, NaNO2 and Ca（NO3）2） were studied by mercury intrusion porosimetry at 3 d and 28 d. The hydration degree of cement pastes was also analyzed. The results show that CaCl2, Na2SO4 and NaNO2 can improve the hydration of cement. The accelerating effect of CaCl2 is dominant, compared to the other salts. CaCl2 can also reduce the porosity of the coarse pores and capillary pores of the pastes, and Na2SO4 can increase the porosity of the coarse pores in cement pastes. The throat size of an interconnected capillary network and the porosity of the capillary pores in pastes with NaNO2 at 28 d decrease. CaCNO3）2 does not improve the cement hydration during 3 d, but it can increase the porosity of the coarse pores or the capillary pores as well as the throat size in the paste at 3 d.