Weibull分布模型改性再生混凝土微观损伤机理分析

Analysis of microscopic damage mechanism of Weibull distribution model modified recycled concrete

为研究再生骨料改性对再生混凝土微观损伤机理的影响,该文用5%硅酸钠溶液(Na_(2)O·nSiO_(2)溶液)和10%聚乙烯醇溶液(PVA溶液)对不同级配再生骨料预浸泡进行改性。通过再生混凝土微小单元强度服从Weibull统计分布对抗压强度进行损伤演化分析和扫描电子显微镜(SEM)对骨料和混凝土微观形貌和机理分析。结果表明:经过5%硅酸钠溶液(Na_(2)O·nSiO_(2)溶液)和10%聚乙烯醇溶液(PVA溶液)改性后的再生混凝土均能显著提升内部微小单元损伤抗性和微观结构的密实性,且5%硅酸钠溶液(Na_(2)O·nSiO_(2)溶液)浸泡改性再生骨料对再生混凝土的提升效果劣于10%聚乙烯醇溶液(PVA溶液)。采用连续级配5~31.5 mm的再生混凝土损伤抗性显著高于单一级配10~16 mm和16~25 mm的再生混凝土损伤抗性。

In order to study the effect of recycled aggregate modification on the microscopic damage mechanism of recycled concrete,5%sodium silicate solution(Na_(2)O·nSiO_(2)solution)and 10%polyvinyl alcohol solution(PVA solution)were used to modify the pre-soaking of recycled aggregate with different gradations.Damage evolution analysis and scanning electron microscopy(SEM)analysis on the microstructure and mechanism of aggregate and concrete were carried out through the compressive strength of recycled concrete micro-units obeying Weibull statistical distribution.The results show that the recycled concrete modified by 5%sodium silicate solution(Na_(2)O·nSiO_(2)solution)and 10%polyvinyl alcohol solution(PVA solution)can significantly improve the damage resistance of internal micro units and the compactness of microstructure,and the improvement effect of recycled aggregate modified by 5%sodium silicate solution(Na_(2)O·nSiO_(2)solution)on recycled concrete is inferior to that of 10%polyvinyl alcohol solution(PVA solution).The damage resistance of recycled concrete with continuous gradation of 5-31.5 mm is significantly higher than that of recycled concrete with single gradation of 10-16 mm and 16-25 mm.