石粉对混凝土力学性能及氯离子扩散系数影响

Influence of Rock Powder on the Mechanical Property and Chloride Diffusion Coefficient of Concrete

为了研究玄武岩石粉对混凝土力学性能和氯离子扩散系数的影响,将玄武岩石粉以替代不同量水泥(内掺)和额外添加(外掺)的方式掺入到混凝土中,分别测试了混凝土的7 d、28 d、56 d、120 d抗压强度和28 d、56 d、120 d氯离子扩散系数,结合微观机理分析了玄武岩石粉对混凝土抗氯离子性能的影响,最后将石粉不同掺量与氯离子扩散系数变化关系进行线性回归分析。研究结果表明:石粉内掺时混凝土抗压强度在5%时小幅度升高,10%～20%时大幅度降低;石粉外掺时混凝土7 d抗压强度随掺量增加持续升高,28～120 d抗压强度先升高后降低。内掺和外掺玄武岩石粉混凝土氯离子扩散系数均有所升高,但石粉内掺时氯离子扩散系数增长趋势较外掺增长趋势明显;随着龄期的增长两种掺石粉方式的氯离子扩散系数变化趋势越来越平缓。通过将石粉内掺和外掺与氯离子扩散系数建立回归曲线及函数表达式,石粉内掺时的函数表达式较石粉外掺时的函数表达式更接近实测值,其相关性系数更高。

In order to study the effect of basaltic rock powder on mechanical property and chloride diffusion coefficient of concrete,the basaltic rock powder was replaced by different amount of cement(internal mixing)and additional addition(external mixing).The compressive strength of 7 d,28 d,56 d and 120 d,and the chloride diffusion coefficient of 28 d,56 d and 120 d were tested respectively.Combined with microscopic mechanism,the effect of basaltic rock powder on the chloride resistance of concrete was analyzed.Finally,a linear regression analysis was made for the relationship between the different dosage of stone powder and the diffusion coefficient of chloride ion.The results of the study show that when the stone powder is internal,the compressive strength of concrete increases at 5%,greatly reduces from 10%to 20%.The compressive strength of concrete 7 d increases continuously with the increase of volume,the compressive strength of 28-120 d first increases and then decreases.The chloride diffusion coefficient of concrete increases with the internal and external stone powder.However,when the stone powder is internal,the growth trend is more obvious than that of external mixing.With the increase of age,the variation trend of chloride diffusion coefficient of two kinds of stone powder is more and more gently.The regression curve and function expression are established by adding the powder and chloride diffusion coefficient.The function expression of internal stone powder is closer to the measured value than the external mixing,the correlation coefficient is higher.With the increase of age,the correlation coefficient of function expression is higher and higher.