桥面现浇混凝土细微裂缝用环氧灌浆材料的环境适应性

Environmental Adaptability of Epoxy Grouting Materials for Micro Cracks in Cast-in-place Cement Concrete for Bridge Deck

为明确混凝土细微裂缝用环氧灌浆材料在极端环境条件下的性能变化情况,采用环氧树脂E-54、聚醚胺D230固化剂与三种活性稀释剂(AD-Ⅰ、AD-Ⅱ和AD-Ⅲ)制备了四种环氧灌浆材料(EP、EP/AD-Ⅰ、EP/AD-Ⅱ和EP/AD-Ⅲ),以冲击强度为评价指标对比分析了四种环氧灌浆材料常温与低温柔韧性,基于环氧灌浆材料拉伸性能与界面粘结强度,探究了EP、EP/AD-Ⅰ、EP/AD-Ⅱ和EP/AD-Ⅲ灌浆材料在高温冲击、温变以及冻融循环工况下的力学性能演变规律。结果表明,与EP灌浆材料相比,活性稀释剂弱化了环氧灌浆材料低温柔韧性、耐高温冲击性、耐温变性以及抗冻性。其中AD-Ⅲ活性稀释剂对环氧灌浆材料常温韧性改善效果最佳,但其-10℃冲击韧性比EP灌浆材料低31.4%;经高温冲击、温变处理以及冻融循环后四种环氧灌浆材料的拉伸性能与粘结强度均出现了不同程度的衰退,高温冲击下四种环氧灌浆材料粘结强度损失较大,降幅高达14.67%,但粘结强度仍高于2.5 MPa;温变工况下环氧灌浆材料粘结强度降幅均在3.5%以内,环氧灌浆材料拉伸性能受冻融循环工况的影响较为显著,但其拉伸强度仍大于40 MPa,断裂伸长率仍高于4.0%。

In order to determine the performance change of epoxy grouting materials for concrete micro cracks under extreme environmental conditions,four kinds of epoxy grouting materials(EP,EP/AD-Ⅰ,EP/AD-Ⅱand EP/AD-Ⅲ)were prepared by using epoxy resin E-54,polyether amine D230 curing agent and three active diluents(AD-Ⅰ,AD-Ⅱand AD-Ⅲ).The impact strength was used as the evaluation index to compare and analyze the flexibility of four kinds of epoxy grouting materials at room temperature and low temperature.Based on the tensile properties and interfacial bond strength of epoxy grouting materials,the evolution law of mechanical properties of different grouting materials under high temperature impact,temperature change and freeze-thaw cycles was explored.The results show that compared with pure epoxy grouting material,the reactive diluent weakens the low temperature flexibility,high temperature impact resistance,temperature denaturation resistance and frost resistance of epoxy grouting materials.Among them,AD-Ⅲactive diluent has the best effect on improving the toughness of epoxy grouting material at room temperature,but its impact toughness at-10℃is 31.4%lower than that of pure epoxy grouting material.After high temperature impact,tempe-rature change treatment and freeze-thaw cycle,the tensile properties and bond strength of four kinds of epoxy grouting materials have different degrees of decline.Under high temperature impact,the bond strength of the four kinds of epoxy grouting materials lost greatly,with a decrease of 14.67%,but the bond strength was still higher than 2.5 MPa.During temperature change conditions,the bond strength of epoxy grouting materials decreases by 3.5%.The tensile properties of epoxy grouting materials are significantly affected by freeze-thaw cycles,but the tensile strength is still greater than 40 MPa,and the elongation at break is still higher than 4.0%.