| 李维红*,向忆寒,包亦望.表层压应力设计提升水泥砂浆的抗折强度[J].实验力学,2022,37(3):315~322 |
| 表层压应力设计提升水泥砂浆的抗折强度 |
| Improving flexural strength of cement mortar by surface compressive stress design |
| 投稿时间：2021-08-19 修订日期：2021-10-08 |
| DOI：10.7520/1001-4888-21-187 |
| 中文关键词: 表层压应力 水泥砂浆 涂层 抗折强度 收缩率 弹性模量 |
| 英文关键词:surface compressive stress cement mortar coating flexural strength shrinkage elastic modulus |
| 基金项目:国家自然科学基金重点项目(52032011)；国家重点研发计划(2018YFF0214500)；省部共建粉体材料与特种陶瓷重点实验室项目(1903)；辽宁省教育厅科学研究经费项目(LJKZ1177) |
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| 中文摘要: |
| 表层压应力可以抵消部分外荷载引起的拉应力，同时阻碍表面裂纹的生成与扩展，从而提升构件抗折强度。本文通过在水泥砂浆试件表面涂覆膨胀剂与水泥混合而成的涂层实现了这种增强方式，同时推导了涂层材料性能及厚度与表层压应力之间的关系，并研究了不同配比涂层对水泥砂浆抗折强度的影响规律。结果表明：为获得足够的表层压应力，涂层的横截面积应尽可能小；表层压应力随基体与涂层弹性模量比值的减小而增大，随涂层与基体收缩率比值的减小而增大。随着涂层中膨胀剂掺量的增加，水泥砂浆试件的早期与后期抗折强度呈现先增大后减小的趋势，膨胀剂掺量为30%的混合涂层对水泥砂浆试件的早期抗折强度提升幅度最大，强度提升率为41.9%；膨胀剂掺量为40%的混合涂层对水泥砂浆试件的后期抗折强度提升幅度最大，强度提升率为34.1%。 |
| 英文摘要: |
| The surface compressive stress can offset the tensile stress caused by some external loads, and hinder the generation and propagation of surface cracks, so as to improve the flexural strength of members.In this paper, the reinforcement method is realized by coating the surface of cement mortar specimen with the coating mixed with expansive agent and cement. At the same time, the relationship between the performance and thickness of coating material and the surface compressive stress is deduced, and the influence of different proportion coatings on the flexural strength of cement mortar is studied. The results of the study indicate that in order to obtain enough surface compressive stress, the cross-sectional area of the coating should be as small as possible. The surface compressive stress increases with the decrease of the elastic modulus ratio of the substrate to the coating, and increases with the decrease of the shrinkage ratio of the coating to the substrate. With the increase of the expansion agent content in the coating, the early and late flexural strength of the cement mortar specimens increases at first and then decreases. The composite coating with 30% expansive agent has the greatest improvement on the early flexural strength of cement mortar specimens, and the strength improvement rate is 41.9%. The composite coating with 40% expansion agent has the largest improvement range of the late flexural strength of cement mortar specimens, and the strength improvement rate is 34.1%. |
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