毛细作用下风积沙混凝土水分和氯离子传输特性试验

Transmission Characteristics of Water and Chloride Ionsin Aeolian Sand Concrete under Capillary Suction

目的研究毛细作用下水分和氯离子在风积沙混凝土中的传输特性,探讨风积沙掺量、氯盐质量浓度对水分和氯离子侵入的影响规律。方法试验制备了5组不同掺量的风积沙混凝土,按照比例为0%、25%、50%、75%、100%等质量替换普通河砂,通过自然扩散法进行风积沙混凝土毛细吸水/盐试验。结果风积沙混凝土毛细吸收曲线前1 d内均呈线性增长,而后逐渐趋于水平;混凝土在氯化钠溶液中的毛细吸收量和毛细吸收系数大于清水溶液,毛细吸收系数随风积沙掺量的增加呈现先减小后增大的趋势,最小值出现在风积沙掺量为25%。风积沙混凝土中水分和氯离子传输深度呈明显线性关系,当水分传输趋于稳定时,氯离子由于扩散作用依旧向内部传输。通过水分和氯离子侵入深度及两者关系,毛细作用下风积沙混凝土中风积沙掺量宜控制在20%~30%。结论风积沙混凝土中水分和氯离子传输非同步,水分渗透速率大于氯离子渗透速率。当水分渗透逐渐稳定时,氯离子会继续向混凝土内部渗透。

The purpose of this paper is to study the transmission characteristics of water and chloride ions in aeolian sand concrete under capillary action,and the influence of aeolian sand content and chloride salt concentration on the intrusion of water and chloride ions.In this experiment,five groups samples of aeolian sand concrete were prepared by 0%,25%,50%,75%,100%mass ratio of aeolian sand replacing the ordinary river sand.And on these samples the capillary water absorption/capillary salt tests were carried out by the natural diffusion method.The results show that the capillary absorption curve of aeolian sand concrete increases linearly in the first 1 d,and then gradually tends to level;The capillary absorption and capillary absorption coefficient for concrete in sodium chloride solution are both greater than that of in clear aqueous solution.The capillary absorption coefficient first decreases and then increases with the increase of the aeolian sand content,when the aeolian sand content is 25%,it reaches the minimum.The transmission depth of water and chloride ions in the aeolian sand concrete is obviously linear.When the transmission of water becomes stable,the chloride ions are still into the The transmission of water and chloride ions in aeolian sand concrete is asynchronous,and the penetration rate of water is greater than that of the chloride ion.due to diffusion.Based on the intrusion depth of water and chloride ions and their relationship,the amount of aeolian sand in the aeolian sand concrete should be controlled at 20%to 30%under capillary action.The transmission of water and chloride ions in aeolian sand concrete is asynchronous,and the penetration rate of water is greater than that of the chloride ion.When the moisture penetration gradually stabilizes,chloride ions is still penetrated continuesly to the inside of concrete.