聚脲包覆混凝土的压缩和吸能特性研究

混凝土结构在受到远超其极限强度的准静态或者冲击载荷作用时,常常发生粉碎性的破坏,导致结构坍塌。采用高弹性材料包覆混凝土有可能减缓结构的灾难性坍塌。该文研究了聚脲涂层包覆的圆柱形混凝土试件在准静态和动态落锤压缩下的破坏过程和吸能特性。实验结果表明混凝土试样的抗压强度存在明显的应变率硬化效应,观察到聚脲包覆混凝土和无聚脲包覆混凝土破坏后期残余承压特性的明显差异。分析了有无聚脲包覆混凝土的破坏形态,结果表明聚脲包覆混凝土的压缩吸能效果远远优于无包覆混凝土,有可能承压吸能构件应用于工程实际。

COMPRESSIVE AND ENERGY ABSORPTION PROPERTIES OF POLYUREA-COATED CONCRETE UNDER QUASISTATIC OR DYNAMIC LOADINGS

When subjected to a quasistatic or dynamic loading that far exceeds the strength limit, a concrete structure may crush or collapse catastrophically. An elastic polymeric material such as polyurea, having high elongation and low modulus, can be sprayed on the concrete structure surface to prevent the structure from collapsing. In this study, we conducted quasi-static compression tests and drop hammer impact tests to study the mechanical behavior of the polyurea-coated and uncoated cylindrical concrete specimens. We compared the differences of the compressive strength, the failure process, and the energy absorption properties of the polyurea-coated and uncoated specimens. The experimental results confirmed that the concrete has an apparent strain rate effect, with the dynamic failure strength higher than the quasistatic failure strength. Although failure strength is hardly affected by the coating, the sustainable compression deformation of the polyurea-coated concrete was significantly greater than that of the uncoated concretes. The polyurea coating increased the energy absorption ability of the concrete subjected to drop hammer impacts.