Abstract: The properties of air-permeability, sorptivity, water-permeability and chloride diffusion of phos-phoaluminate cement (PAC) concrete were investigated in detail, and the mechanism was discussed as well. The phase composition and morphology of hydration products, porosity and por"e size distribution, and electrical properties of PAC concrete cured for 28 days were analyzed with X-ray diffraction (XRD), mercury intrusion porosimetry(MIP) and electrochemical impedance spectroscopy (EIS). It is indicated that the properties of PAC concrete are better than that of PC. The air-permeability coefficient and sorptivity of PAC concrete cured for 28 days is 0.013 7Xln(/>/mbar)/min and 0. 045 6X10~7 m'/min05 respectively, the water permeability coefficient is 2. 99 X 10~9 mm/s, the chloride diffusion coefficient is 1. 61 X 10~12 m2/s. This shows that the hydration mechanism and the hydration products of PAC are different from that of PC. The permeability coefficient of concrete reduces with age, which is due to continuous formation of more hydration products.%研究了磷铝酸盐水泥(PAC)混凝土表面透气、表面吸水、水渗透和氯离子渗透性能,并对它们的机理进行了探讨.利用X射线衍射仪(XRD),全自动孔隙分析仪(MIP)和电化学工作站(EIS)对混凝土水化产物的物相组成、孔结构特性和电性能进行了分析.结果表明:磷铝酸盐水泥混凝土具有较佳的表面性能、抗水渗透和抗氯离子渗透性能,养护28 d的PAC混凝土表面透气系数为0.013 7×ln( p/mbar) /min,表面吸水系数约为0.045 6×10-7m3/min0.5,相对渗水系数约为2.99×10-9 mm/s,氯离子扩散系数约为1.61×10-12 m2/s.这是由于磷铝酸盐水泥水化机理和水化生成物不同于硅酸盐水泥造成的.随着养护龄期的增长,PAC的水化生成物增多,结构更加致密,混凝土抗渗性能亦随之提高.
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