关键词: 风积沙;混凝土;盐侵;冻融;扩散;耐久性

Abstract: Aeolian sand concrete was made by replacing the ordinary river sand partially or totally with abundant aeolian sand. And by the accelerated testing and chemical analysis methods,the chloride ions'concentration of the concrete with different aeolian sand content (0 ,20%,40%,60%,80%,100%) was measured when the aeolian san concrete suffered from the freeze-thaw under corrosive environment of the chloride salt. Meanwhile,the combining capacity and diffusion coefficient of the chloride ions in the aeolian sand concrete was also calculated. In addition,the test samples were analyzed by means of X-ray diffraction analysis (XRD). The results indicate that the free chloride ions'concentration of the aeolian sand concrete suffered from the freeze-thaw under corrosive environment of the chloride salt raises gradually with the increase of the freeze-thaw times. Besides,the combination of chloride ions is characterized by the Langmuir nonlinear adsorption and the combined ability coefficient k is introduced to characterize the combining capacity of the chloride ions in the aeolian sand concrete. With the increase of freeze-thaw times,the diffusion coefficient of chloride ions in the concrete with different aeolian sand content is decreasing,while the substitution amount of the aeolian sand has less influence on the diffusion coefficient of chloride ions in the concrete after 75 times of freeze-thaw. Consequently,there is a coupling relationship between the effects of the number of freeze-thaw cycles and the substitution amount of the aeolian sand on the diffusion coefficient of chloride ions in the concrete.

Key words: aeolian sand;concrete;salt intrusion;freeze-thaw;diffusion;durability