工程水泥基复合材料配合比对其拉伸性能及耗能特性的影响

Effect of Mix Ratio on the Uniaxial Tensile Performance and Energy Dissipation Property of Engineered Cementitious Composites

工程水泥基复合材料(Engineered cementitious composites,ECC)在工程结构修复加固等领域应用广泛。制备了12组不同配比且不同养护龄期的ECC试件进行单轴拉伸试验,研究了不同砂胶比、水胶比、硅灰掺量、纤维掺量及养护龄期对ECC拉伸性能及耗能特性的影响,优化了ECC的配合比范围。结果表明:ECC的初裂强度和峰值强度在水胶比的一定范围内随水胶比的降低而增加,水胶比的建议区间为0.24~0.30;砂胶比在一定范围内的增加会导致ECC的初裂强度和峰值强度显著提高,砂胶比增加且不超过0.66时断裂能、延性指数(耗能能力)均呈现线性增加,砂胶比的建议区间为0.60~0.66;纤维掺量增加对ECC的断裂能和裂纹扩展有一定提高,但会使强度降低,纤维掺量的建议值为1.6%;适当的硅灰掺量能有效增加抗拉应变能力。

Engineered cementitious composites(ECC)in structural repair and reinforcement are widely used.In this test,12 sets of ECC with different mix ratios and different curing ages were prepared for uniaxial tensile tests,the effects of different proportions of sand-binder ratios,water-binder ratios,silica fume content and fiber content and ages on the tensile properties and energy dissipation properties of ECC were analyzed.Besides,the mix ratio range of ECC was also optimized.The results show that the initial cracking strength and peak strength of ECC increase with the decrease of the water-binder ratio within a specific range,and the recommended range of the water-binder ratio is 0.24-0.30.The initial crack strength and peak strength of ECC significantly increase when the sand-binder ratio to cement increases within a specific range.When the sand-binder ratio is increased and does not exceed 0.66,the fracture energy and ductility index(energy dissipation capacity)linearly increase,and the recommended range of the sand-binder ratio is 0.60-0.66.The fracture energy and crack growth of ECC are improved with the increase of fiber content,but the strength decreases,and the effect is limited.The recommended value of fiber content is 1.6%.Appropriate silica fume content can effectively increase the tensile strain capacity.