干湿循环作用对非饱和锂渣混凝土氯离子扩散性能的影响

Effect of Dry-Wet Cycles on Diffusion Properties of Chloride Ions in Unsaturated Lithium Slag Concrete

针对经受干湿循环作用下氯离子侵蚀致使混凝土耐久性劣化的问题,采用在不同环境相对湿度条件下浸泡和喷淋的方式模拟干湿循环作用,通过测定侵入混凝土试件内部不同深度的自由氯离子含量和氯离子总含量,借鉴生长曲线函数中的Hill模型,探讨了干湿循环作用下,锂渣的掺量、环境相对湿度以及侵蚀氯盐质量分数等因素对混凝土氯离子扩散性能的影响。研究结果表明:干湿循环作用下,随着环境相对湿度的降低和侵蚀氯化钠溶液质量分数的增大,侵入混凝土内部的氯离子总含量达到阀值所需要的时间逐渐延长。锂渣替代水泥20%时,Hill系数n值最小,侵入混凝土内部氯离子总含量达到阀值所需要的时间最长。锂渣混凝土内部取样深度1～5 mm时,自由氯离子含量排序为(RH=40%条件)>(RH=80%条件)>(RH=60%条件)>(RH=100%条件)。干湿循环作用下,混凝土内部的氯离子总含量并不随着相对湿度的递减而单调增加。

Reinforcement corrosion caused by chloride ion erosion is the main cause of the concrete durability degradation,and under the act of dry-wet cycles through the chloride ion erosion causes the damage of the concrete durability degradation is more serious.Based on the relative humidity in a different environment under the condition of soaking and spraying way to assimilate the dry-wet cycles role,through decides of invasion of different depth of free chloride ion content in the concrete specimen,use the experience of the Hill model to explore the growth curve under act of dry-wet cycles,environmental relative humidity and dosage of lithium slag erosion chlorine salt concentration on perform concrete chloride ion diffusion affect,the results show the dry-wet cycles,chloride ions into inside the concrete the time needed to reach the threshold as the reduce of environmental relative humidity and erosion gradually extend the increase of concentration of sodium chloride solution;When lithium residue is 20%of cement,the value of Hill coefficient n is the smallest,which means the total amount of chlorine ion in the concrete is the maximum time needed to reach the valve value.Internal lithium slag concrete chloride ion concentrations of different depth in 1~5 mm depth within the scope of free chlorine ion concentration order for(RH=40%)>(RH=80%)>(RH=60%)>(RH=100%),dry-wet cycles inside the concrete under the act of chloride ion content is not increased monotonously with the decreasing of relative humidity.