Research on the durability of composite epoxy resin modified repair mortars based on water-oil gradient phase change: From macroscopic to nanoscopic scales

IF 7.4 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Construction and Building Materials Pub Date : 2024-11-30 DOI:10.1016/j.conbuildmat.2024.139325

Heping Zheng , Yuying Duan , Bo Pang , Meng Wang , Pan Wang , Dongshuai Hou

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引用次数: 0

Abstract

With the rapid pace of urbanization, global demand for concrete is increasing, shifting focus from construction to repair and maintenance. Traditional cement-based repair materials generally suffer from brittleness and poor durability, failing to meet the growing demand for durable repair solutions. We developed a water-oil gradient composite epoxy resin (CEP) modified cement-based repair mortar (MCEP) using self-synthesized water-based epoxy resin (WEP) and oil-based epoxy resin (EP). Durability tests showed that CEP-modified cement mortar exhibited improved resistance to solution penetration, shrinkage, acid corrosion, and freeze-thaw cycles, with increased CEP content positively affecting mortar durability. Notably, the addition of CEP not only enhanced the interface bonding strength between MCEP and old concrete but also maintained good bonding stability under moisture erosion. X-CT and SEM microstructural tests revealed that CEP is evenly distributed in the cement paste, forming a cement-polymer interpenetrating network structure, which improves crack resistance and reduces solution penetration in MCEP. Molecular dynamics simulations explored the adsorption of CEP on calcium aluminate hydrate (AFt), a key cement hydration product, and the moisture transport mechanisms in AFt and CEP-modified AFt nanopores. Results indicated that CEP molecules adsorb onto AFt via ionic and hydrogen bonds, demonstrating good stability. During moisture penetration, CEP reduced water transport efficiency in the nanopores. CEP modification improved the crack resistance and durability of cement repair mortars, providing valuable insights into molecular-scale enhancements in water permeability resistance. This study aims to contribute to the design and practical application of water-oil gradient epoxy resins and other polymer-modified cement-based repair materials.

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基于水-油梯度相变的复合环氧树脂改性修补砂浆耐久性研究：从宏观到纳米尺度

随着城市化的快速发展，全球对混凝土的需求不断增加，将重点从建设转向维修和维护。传统的水泥基修复材料普遍存在脆性和耐久性差的问题，无法满足人们对耐久性修复方案日益增长的需求。以自合成水基环氧树脂（WEP）和油基环氧树脂（EP）为原料，研制了一种水-油梯度复合环氧树脂（CEP）改性水泥基修补砂浆（MCEP）。耐久性试验表明，CEP改性水泥砂浆具有更好的抗溶液渗透、收缩、酸腐蚀和冻融循环性能，CEP含量的增加对砂浆耐久性有积极影响。值得注意的是，CEP的加入不仅提高了MCEP与老混凝土的界面粘结强度，而且在水分侵蚀下保持了良好的粘结稳定性。X-CT和SEM微观结构测试表明，CEP在水泥浆体中分布均匀，形成水泥-聚合物互穿网络结构，提高了MCEP的抗裂性，降低了溶液渗透。分子动力学模拟研究了CEP在水泥关键水化产物水合铝酸钙（AFt）上的吸附，以及水在AFt和CEP修饰的AFt纳米孔中的输运机制。结果表明，CEP分子通过离子键和氢键吸附在AFt上，具有良好的稳定性。在水分渗透过程中，CEP降低了纳米孔中的水输送效率。CEP改性提高了水泥修补砂浆的抗裂性和耐久性，为在分子尺度上增强抗水渗透性提供了有价值的见解。本研究旨在为水油梯度环氧树脂及其他聚合物改性水泥基修复材料的设计和实际应用做出贡献。

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来源期刊

Construction and Building Materials 工程技术-材料科学：综合

CiteScore

13.80

自引率

21.60%

发文量

3632

审稿时长

82 days

期刊介绍： Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged. Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.