酸性环境中富水充填材料腐蚀及劣化机理

为了研究酸性环境对富水充填材料的影响,通过强度检测、扫描电镜、能谱分析及X射线衍射( XRD)等实验手段,分析富水充填材料在酸性环境中浸泡后的宏观性能及微观结构变化,并探讨其腐蚀及劣化机理.结果表明：富水充填材料在pH值为1和3的盐酸溶液中浸泡180 d后抗压强度比标养28 d的强度分别降低88.8%和58%,在pH值为3的硫酸溶液中浸泡后降低68%,pH值为1的硫酸溶液中浸泡后强度降为零；微观实验结果显示随着富水充填材料在硫酸溶液中浸泡时间的延长,试件内部有二水石膏生成,盐酸溶液中试件仅在pH值为1的溶液中浸泡180 d后产生二水石膏；盐酸溶液对富水充填材料的腐蚀主要为H+中和作用下硬化体结构的溶解腐蚀,硫酸溶液对材料的腐蚀为硬化体结构的溶解腐蚀和石膏的膨胀腐蚀；硫酸溶液对富水充填材料的腐蚀作用强于盐酸溶液.

Corrosion and deterioration mechanism of water-rich filling materials in acid solution

To study the impact of acid environment on the water-rich filling materials, experimental methods including intensity detection, scanning electron microscopy and X-ray diffraction were used to analyze the macro and micro changes of water-rich filling materials in acid environment and to discuss the corrosion and deterioration mechanism. After soaking for 180 d in hydrochloric solu-tions of pH 1 and pH 3, the compressive strength of the materials decreases by 88. 8% and 58%, respectively, compared with that of standard curing for 28 d. After soaking in a sulfuric acid solution of pH 3, the compressive strength decreases by 68%. When the ma-terials were soaked in a sulfuric acid solution of pH 1, the compressive strength is zero. Microscopic tests show that dihydrate gypsum is generated in the materials with the prolongation of immersion time in the sulfuric acid solution. In the hydrochloric acid solution, di-hydrate gypsum is produced only in the solution of pH 1 after soaking for 180 d. The corrosion of the hydrochloric acid solution on the materials is mainly the dissolution corrosion of hardened structure with the neutralization effect of H+. The corrosion of the sulfuric acid solution on the materials is the dissolution corrosion of hardened structure with the neutralization effect of H+ and the expansion corrosion of dihydrate gypsum. The corrosive action of the sulfuric acid solution on the materials is stronger than that of the hydrochlo-ric acid solution.