孔隙结构对石轻混凝土抗压强度和氯离子渗透性能影响

Effects of pore structure of gravel lightweight concrete on compressive strength and chloride ion permeability

为了探讨石轻混凝土孔隙结构对抗压强度、氯离子渗透及变形性能影响,采用气孔分析仪测试了普通碎石在不同取代率时的孔径变化范围,分析了平均孔径、孔径率和孔隙率对上述参数影响规律。结果表明:抗压强度、氯离子渗透和变形性能的决定因素不是平均孔径和孔隙率,而是20~100、100~200、200~500μm范围内孔径率和累积孔径率及其分布均匀性。其中,抗压强度在取代率为35%时达到最大,此时平均孔径和100~200μm范围内孔径率均最大,但在上述孔径范围内孔径率相差幅度不大,累积孔径率和孔隙率为最小;6 h电通量降低幅度在取代率为15%时最小,虽然孔隙率较大,但决定于小于100μm孔径及上述孔径范围分布;因强度与比强度和弹性模量的相关性,同样表现为取代率为35%时抗损伤变形能力最强。

To investigate the effects of pore structure of gravel lightweight concrete(GLWC)on compressive strength,chloride ion penetration resistance and deformation properties,the range of pore diameter of GLWC under different substitution rates of gravel was tested by stomatal analyzer,and the influence rule of average pore diameter,aperture rate and porosity on the above parameters was analyzed.The results show that the determining factors of the above parameters are not average pore diameter and porosity,but the aperture rate and cumulative aperture rate and their distribution uniformity in the ranges of 20~100μm,100~200μm and 200~500μm respectively.Where the compressive strength reaches the maximum at replacement rate of 35%,both the average pore diameter and aperture rate within the range of 100~200μm are the maximum,the difference of aperture rate within the above pore diameter ranges is not larger,and the cumulative aperture rate and porosity are the minimum.The corresponding lowering of electrical flux after 6 h is the smallest at substitution rate of 15%,which is determined by the pore diameter less than 100μm and distribution of the above pore diameter range,although the porosity is larger.Due to the correlations between strength and strength to density ratio and elastic modulus respectively,the resistance to damage and deformation is the strongest at substitution rate of 35%.