震后建筑垃圾再生混凝土高温强度和损伤机理研究

Little research had been done to study of Recycled aggregate concrete (RAC) behavior of thermal strength. In this present project, the fundamentally properties of recycled aggregate (RA) and RAC which made from building scrap came from "WenChuan Earthquake" disaster area were respectively analyzed. The mechanical behavior of RAC were summarized.The propriety water-cement ratio and optimum scheme made RAC were proposed. And, the experimwntal investigations of RAC performance of hot modulus rupture which are made from different proportion of RA was analyzed. The correlation of proportion of RA, speed of elevated temperature and temperature was established.Then, the properties of thermal fatigue affected by dynamic load of RAC with different proportion of RA were researched by means of experiment. The relation between the value of dynamic load, fatigue stress amplitude, expanding of fatigue cracks and fatigue life were analyzed.Finally, the micro-structural mechanism and interior composition observations of the specimens compared before and after the high temperature by means of microcosmic analysis and tesing technique were obtained. The characteristics of RAC thermal strength from microcosmic variety aspect were illuminated. And also, the measure of improved performance was proposed. Actualized this projet, it can be proved that it is feasible to support in the development and extensive application and provide many references for practical engineering applications and further study.

再生混凝土材料高温强度(抗折性能、高温疲劳性能)及其损伤破坏机理分析尚不完全明了。本项目拟针对汶川大地震产生的巨量建筑固体废弃物进行材料力学性能实验，确定其基本力学性能指标和再生混凝土配置合理配合比和优化配置方案。并对不同再生骨料取代率的再生混凝土材料试件进行高温抗折性能实验分析和研究，得出取代率、升温速率、温度等与高温抗折强度之间的耦合关系。且对不同再生骨料取代率的再生混凝土进行高温动态载荷疲劳性能试验研究，分析其动态载荷量值、疲劳应力幅值、疲劳裂纹扩展、疲劳寿命之间的相互关联。最后，利用微观分析测试技术，研究材料高温作用前后内部破坏机理和内部成分构成，从微观变化揭示再生混凝土高温强度性能，提出改善其性能的合理措施。本项目的开展，为震后建筑垃圾快速处理及资源化利用等提供技术支持，为其今后的实验研究和工程应用提供依据。

近年来研究表明，针对再生混凝土材料高温强度高温疲劳性能及其损伤破坏机理分析、结构合金材料长寿命（超高周）服役条件下动力灾变的渐进性损伤特征及力学机制、强震下建筑结构钢灾变性损伤特征及低周疲劳性能等方面开展研究是有重要工程意义的。.本项目对汶川大地震产生的巨量建筑固体废弃物进行材料力学性能实验，确定其基本力学性能指标和再生混凝土配置合理配合比和优化配置方案。并对不同再生骨料取代率的再生混凝土材料试件进行高温性能实验分析和研究，得出取代率、升温速率、温度等强度之间的耦合关系。且对不同再生骨料取代率的再生混凝土进行高温动态载荷疲劳性能试验研究，分析其动态载荷量值、疲劳应力幅值、疲劳裂纹扩展、疲劳寿命之间的相互关联。利用微观分析测试技术，研究材料高温作用前、后内部破坏机理和内部成分构成，从微观变化揭示再生混凝土高温强度性能，提出改善其性能的合理措施；并进行了不同掺合物的再生混凝土的性能研究，扩展了地震再生混凝土的研究范围。.作为土木工程领域发展，材料和结构整体研究是主要工作范围。针对结构合金材料开展长寿命（超高周）服役条件下动力灾变的渐进性损伤特征及力学机制、强震下建筑结构钢灾变性损伤特征及低周疲劳性能也做了一定的试验研究分析。本项目的开展，为震后建筑垃圾快速处理及资源化利用及结构钢疲劳性能研究等提供技术支持，为其今后的实验研究和工程应用提供依据。