摘要
实际防渗工程中有时会将聚脲材料同网格布组合为复合防渗涂层,但其聚脲材料与网格布的耦合作用机理和破坏模式缺乏研究,而且该种复合涂层在实际应用中亦存在脱落、水解、耐久性差等问题。因此本文基于试验和数值分析,探讨网格布纤维同聚脲材料的耦合作用,考察网格布与聚脲涂层耦合作用的受力变形行为和破坏模式,分析不同纤维-基体材料组合形式下的变形性能和承载性能。研究结果表明:纤维断裂导致聚脲材料出现瞬间应力突变,纤维断裂面及应力突变引发的微裂纹导致整体截面拉断。聚脲材料强度较高,设置网格布后会导致涂层产生损伤缺陷,使得强度及伸长率大幅下降,伸长率降幅达到75%以上,因此网格布对聚脲材料性能起到负面效应。同样研究表明,聚氨酯材料强度相对较低,设置网格布后强度增幅约为14%,网格布对聚氨酯材料起到一定加强效果,但同样会导致伸长率大幅降低。由于网格布的伸长率及强度决定了复合涂层的伸长率及强度,因此在实际工程应用中,出现以下条件之一时不应在聚脲基体材料中设置网格布:(a)对止水防渗涂层伸长率要求高于网格布破坏伸长率;(b)基体材料强度大于网格布强度;(c)基体材料强度大于涂层-基面切向粘接强度。目前现有聚脲的相关标准及规范中的物理力学性能均未使用网格布进行加强,且科学定义的聚脲的相应标准及规范中所提的材料指标也均符合本研究所建议的不应加网格布的相应条件,因此建议工程中使用的聚脲材料不应设置网格布。
Polyurea is an excellent caulk-sealing and surface anti-seepage material.Composite coating composed of polyurea and mesh fabric can be found in some projects.However,this combination is only a simple imitation of the traditional polyurethane-mesh-fabric composite coating structure.Research on the coupling behavior and failure mechanism of this composite coating can rarely be found.Problems such as peeling,hydrolysis,and poor durability occurred.This study investigated the coupling effect between the mesh fabric and polyurea substrate,and explored the mechanical behavior and failure pattern of mesh fabric reinforced polyurea coating.The deformation behavior and load-carrying capacity of different material combinations were also analyzed.The main conclusions are as follows:Fabric fiber fracture leads to instantaneous stress pulse in the polyurea substrate,fiber fracture surface and stress-pulse-induced microcracks lead to the overall cross-section pull-off failure.The polyurea material exhibits a higher strength.Mesh fabric induced defects leads to an elongation decrease of more than 75%.The mesh fabric could undermine the strength and deformation capacity of the polyurea substrate,playing a negative role on the material performance.The polyurethane material generally exhibits a lower strength.The mesh fabric could increase the tensile strength by 14%.The mesh fabric could increase the strength of the polyurethane coating substrate,bringing a certain strengthening effect.However,the break elongation could also be decreased.As the elongation and strength of the mesh fabric dominates that of the composite coating,in practical engineering applications,the mesh fabric should not be adopted when meeting the following conditions:(a)the coating elongation requirements are higher than that of the mesh fabric;(b)the substrate material strength is greater than the mesh fabric;(c)the substrate material strength is greater than the coating-substrate tangential bonding strength(e.g.3.2 MPa for concrete substrate).At present,the
作者
李炳奇
张继磊
刘小楠
孟天一
LI Bingqi;ZHANG Jilei;LIU Xiaonan;MENG Tianyi(State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing 100038,China)
出处
《水利学报》
EI
CSCD
北大核心
2024年第8期883-897,共15页
Journal of Hydraulic Engineering
基金
中国水科院基本科研业务费专项(SS110145B0022021)。
关键词
网格布
聚脲
网格布-聚脲涂层
精细化模型
拉伸试验
mesh fabric
polyurea
mesh fabric reinforced polyurea coating
detailed model
tensile test
