冲击荷载下低温混凝土力学特性试验研究

发布时间：2018-04-14 10:02

本文选题：冲击荷载 + 低温　；参考：《安徽理工大学》2016年硕士论文

【摘要】：近年来,社会经济的发展带动了全国性的铁路、公路、桥梁、港口、隧道、地铁、市政等基础设施的快速建设,混凝土工程材料的的应用更加广泛、越来越多。在我国北部、西部寒冷地区以及一些低温复杂环境中施工时,为确保工程质量,还必须对混凝土低温条件下的物理力学性质有充分的掌握,包括低温时的的抗冲击性能。在实验室配制混凝土材料,制取试块和试样,在TYE-2000型压力试验机上进行静态力学试验,测试混凝土材料的静态力学性质；应用大杆径74mm SHPB试验装置进行常温和不同低温条件下冲击试验,分析不同温度下混凝土试样的动态力学性能。通过对试验数据的分析研究得出：①混凝土材料,动态荷载作用时其破坏强度要大于静载时的破坏强度；②当冻结温度相同时,干燥和饱水时混凝土试样最大破坏应力相近,后者略大于前者；③负温时随着温度降低,混凝土材料内部孔隙和节理中的水分发生凝固,一方面使混凝土材料脆性增强,致使破坏后形态逐渐大块化；另一方面水分凝固的同时,增大了水分与骨料、骨料与骨料之间的胶着力和凝聚力,致使混凝土材料抗压强度增大,发生破坏时最大应力增大。试验研究揭示了冲击载荷作用下低温混凝土材料的演化机理和动态应力一应变响应关系,为低温条件下混凝土工程设计和施工提供了有益参考。
[Abstract]:In recent years, the development of social economy has led to the rapid construction of national railway, highway, bridge, port, tunnel, subway, municipal and other infrastructure facilities, and the application of concrete engineering materials is more and more extensive.In order to ensure the engineering quality, the physical and mechanical properties of concrete under low temperature conditions must be fully grasped, including the impact resistance at low temperature.The concrete materials were prepared in the laboratory and the test blocks and samples were made. The static mechanical tests were carried out on the TYE-2000 pressure testing machine to test the static mechanical properties of the concrete materials.The dynamic mechanical properties of concrete specimens at different temperatures were analyzed by means of impact tests at room temperature and at different low temperatures with a large diameter 74mm SHPB test device.Through the analysis of the test data, it is concluded that the failure strength of the concrete under dynamic loading is higher than that under static load. When the freezing temperature is the same, the maximum failure stress of the concrete specimen under drying and saturated water is similar.When the latter is slightly larger than the former, when the temperature decreases, the internal pores and the moisture in the joints solidify. On the one hand, the brittleness of the concrete material is enhanced, which leads to the gradual formation of bulk after failure.On the other hand, water solidification increases the adhesive force and cohesion between water and aggregate, which results in the increase of compressive strength of concrete and the maximum stress when failure occurs.The experimental study reveals the evolution mechanism and dynamic stress-strain response of low temperature concrete under impact loading, which provides a useful reference for the design and construction of concrete under low temperature.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU528

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