耐候塑化涂料在混凝土护栏中的应用研究

Application of Weather-Resistant Plasticized Coating in Concrete Barrier Protection

摘要: 为减少冻融循环、干湿交替、氯离子侵蚀和碳化等劣化因素对混凝土护栏服役性能的影响，本文从物理劣化、化学劣化和生物劣化三个方面分析混凝土护栏主要病害形成机理，指出防止水、氯离子和CO₂侵入是提升护栏耐久性的关键。在比较成膜型、渗透型和孔隙封闭型防护材料特点的基础上，结合室内性能指标和安徽地区多座桥梁护栏工程应用情况，对耐候塑化涂料的防护性能与施工工艺进行研究。结果表明，该涂料表干时间 ≤ 4 h，实干时间 ≤ 8 h，附着力 ≥ 1 MPa，裂缝追随性 ≥ 20 mm，静态水接触角 ≥ 120˚，VOC含量 < 50 g/L；固化后涂层在耐水、耐热、耐湿热、耐紫外、耐盐雾、耐酸碱和融雪盐冻融循环200次等条件下保持表面平整致密，无明显起泡、脱落和起皱，抗氯离子渗透系数 ≤ 8.67 × 10⁻¹⁴ m²/s。现场应用显示，涂层施工完成7 d后表面均匀完整，8个月跟踪观测未见明显剥落、破损和大范围起泡。研究表明，耐候塑化涂料具有良好的憎水性、裂缝适应性、抗氯离子渗透能力和施工适应性，可用于混凝土护栏防腐养护工程，尤其适用于受融雪盐、冻融循环及大气侵蚀影响较大的道路桥梁环境。

Abstract: To reduce the adverse effects of freeze-thaw cycles, wet-dry alternation, chloride ion ingress, and carbonation, this study focuses on the durability of concrete barriers. The deterioration mechanisms of concrete barriers are analyzed from three aspects: physical deterioration, chemical deterioration, and biological deterioration. The results indicate that preventing the ingress of water, chloride ions, and CO₂ is essential for improving durability. This study compares film-forming, penetrating, and pore-blocking protective materials. A weather-resistant plasticized coating is then selected for further investigation. Its protective performance and construction process are studied through laboratory tests and field applications. The field applications were carried out on several bridge concrete barriers in Anhui Province. The results show that the surface-drying time of the coating is no more than 4 h. The hard-drying time is no more than 8 h. The adhesion strength is not less than 1 MPa. The crack-following ability is not less than 20 mm. The static water contact angle is not less than 120˚. The volatile organic compound content is less than 50 g/L. After curing, the coating forms a continuous and compact protective layer on the concrete surface. The coating remains dense and intact under water immersion, heat exposure, damp-heat aging, ultraviolet radiation, salt spray, acid exposure, and alkali exposure. It also remains stable after 200 cycles of deicing-salt freeze-thaw action. No obvious blistering, peeling, or wrinkling is observed. The chloride ion permeability coefficient is no more than 8.67 × 10⁻¹⁴ m²/s. This indicates good resistance to chloride penetration. Field observations show that the coating surface is uniform and complete 7 days after construction. After 8 months of service, no obvious peeling, damage, or large-area blistering is observed. The study shows that the weather-resistant plasticized coating has good hydrophobicity. It also has good crack adaptability, chloride resistance, and construction applicability. Therefore, it can be used for the protective maintenance of concrete barriers. It is especially suitable for road and bridge environments affected by deicing salts, freeze-thaw cycles, and atmospheric exposure.