不同取代率再生骨料混凝土硫酸根离子扩散试验

Sulfate Ion Diffusion Test of Recycled Aggregate Concrete with Different Replacement Ratio

再生骨料混凝土能很好的解决城市建筑垃圾过多、天然骨料资源不足的问题。耐久性对于再生骨料混凝土在实际工程中的应用十分重要,混凝土常常会受到硫酸盐侵蚀而影响其耐久性。通过把0%、30%、50%、70%、100%取代率的再生骨料混凝土放入5%的硫酸钠溶液中,分别侵蚀2、4、6、8、10、12个月,每个侵蚀周期都对样品进行分层取样,采用EDTA络合滴定法检测硫酸根离子含量,从而得出侵蚀12个月后的不同取代率再生骨料混凝土硫酸根离子分布:0%取代率再生骨料混凝土硫酸根离子含量由初始值0.43%增加到2.24%,侵蚀深度为21 mm;30%取代率再生骨料混凝土硫酸根离子含量由初始值0.54%增加到2.66%,侵蚀深度为21 mm;50%取代率再生骨料混凝土硫酸根离子含量由初始值0.61%增加到3.40%,侵蚀深度为24 mm;70%取代率再生骨料混凝土硫酸根离子含量由初始值0.70%增加到3.98%,侵蚀深度为27 mm;100%取代率再生骨料混凝土硫酸根离子含量由初始值0.85%增加到5.02%,侵蚀深度为30 mm;若以0%取代率再生骨料混凝土硫酸根离子含量和侵蚀深度为基准,30%、50%、70%、100%取代率的再生骨料混凝土硫酸根离子含量同比分别增长17.13%、54.14%、81.22%、130.39%;30%、50%、70%、100%取代率的再生骨料混凝土侵蚀深度同比分别增长0%、14.29%、28.57%、42.86%。并结合试验结果,详细分析了不同取代率对于再生骨料混凝土硫酸根离子扩散影响的机理,为再生骨料混凝土在实际工程中的应用提供了借鉴。

Recycled aggregate concrete can be a good solution to the problem of excessive urban construction waste and lack of aggregate resources. Durability is very important for the application of recycled aggregate concrete in practical engineering, concrete is often subjected to sulfate attack to durability. Through respectively putting 0%, 50%, 30%, 70%, 90% replacement rate of recycled aggregate concrete was put into 5% sodium sulfate solution for corrosion of ：2,4,6,8,10,12 months, stratified sampling of the sample was performed on each erosion cycle, through using EDTA complex titration method to test sulfate ion that erode for 12 months. The diffusion law of sulfate ion can be listed as follow ： The sulfate content of 0% replacement rate of recycled aggregate concrete is increased from 0.43% to 2. 24%, and the erosion depth is 21 mm. The sulfate content of 30% replacement rate of recycled aggregate concrete is increased from 0. 54% to 2. 66%, and the erosion depth is 21 mm. The sulfate content of 50% replacement rate of recycled aggregate concrete is increased from 0. 61% to 3.40%, and the erosion depth is 24 mm. The sulfate content of 70% replacement rate of recycled aggregate concrete is increased from 0.70% to 3.98%, and the erosion depth is 27 mm. The sulfate content of 100% replacement rate of recycled aggregate con- crete is increased from 0. 85% to 5.02%, and the erosion depth is 30 mm. In terms of 0% replacement rate of re- cycled aggregate concrete as the base erosion after 12 months of sulfate content and erosion depth, 50%, 30%, 70%, 100% replacement rate of recycled aggregate concrete sulfate content increased respectively by 17.13%, 54. 14%, 81.22%, 130.39%. 0%, 50% , 70%, 100% replacement rate of recycled aggregate concrete erosion depth increased respectively by 0%, 14.29%, 28.57% ,42. 86%. And combined with the experimental results, the mechanism of the effect of different substitution rates on the diffusion of sulfate ion in recycled aggregate con- crete is analyzed in detail. It provides a reference for the application of recycled aggregate concrete in practical engi- neering.