不同介质环境下改性再生混凝土冻融损伤分析及寿命预测

Freeze-thaw damage analysis and life prediction of modified recycled concrete under different medium environments

为探究不同冻融环境下改性再生混凝土耐久性问题,该文选取5%水玻璃溶液和8%硅烷溶液分别对再生骨料浸泡进行单一改性和复合改性。对改性后的再生混凝土分别置于清水、3.5%NaCl溶液和5%Na2SO4溶液3种介质环境中进行快速冻融试验,通过再生混凝土质量损失和相对动弹性模量变化分析其劣化机理,并引入Weibull模型对再生混凝土进行损伤和寿命预测。结果表明:相同冻融环境下,再生骨料经过改性处理后的再生混凝土抗冻耐久性改善明显,且复合改性改善效果优于单一改性效果。同一试验组在不同冻融环境下的损伤程度依次为3.5%NaCl溶液>5%Na2SO4溶液>清水。引入Weibull模型能较好地反映不同环境下改性再生混凝土的冻融损伤和预测寿命,为改性再生混凝土应用于实际工程提供理论基础和参考依据。

In order to explore the durability of modified recycled concrete under different freeze-thaw environments,this paper selects 5%water glass solution and 8%silane solution to carry out single modification and composite modification of recycled aggregate soaking,respectively.The modified recycled concrete is placed in three medium environments of clear water,3.5%NaCl solution and 5%Na2SO4 solution for rapid freeze-thaw test.The deterioration mechanism is analyzed by the mass loss and relative dynamic elastic modulus of recycled concrete,and the Weibull model is introduced to predict the damage and life of recycled concrete.The results show that under the same freeze-thaw environment,the frost resistance durability of recycled concrete after modified recycled aggregate is obviously improved,and the improvement effect of composite modification is better than that of single modification.The damage degree of the same test group in different freeze-thaw environments was 3.5%NaCl solution>5%Na2SO4 solution>water.The Weibull model can better reflect the freeze-thaw damage and life prediction of modified recycled concrete under different environments,and provide theoretical basis and reference for the application of modified recycled concrete in practical engineering.