井壁高性能混凝土防腐蚀机理与性能试验

Anti-corrosion mechanism and performance test of high-performance concrete for shaft wall

混凝土腐蚀是其力学性能衰减的重要因素,西北地区地下工程混凝土常受硫酸盐腐蚀的影响,造成结构失稳或达不到设计使用年限。以赵石畔井筒含水层为工程背景,分析井壁混凝土防腐措施,探究掺防腐剂混凝土的微观形态差异和仿钢纤维提高混凝土的力学性能。发现掺加复合防腐剂的混凝土试件的微观结构相对密实,能够降低可侵入混凝土中硫酸根离子浓度并细化毛细孔的孔径;仿钢纤维对井壁混凝土强度具有明显的增强作用,能够显著改善C50、C60、C70井壁混凝土的力学性能。根据井筒含水层水质特点,给出了井筒各段混凝土的复合防腐剂和仿钢纤维的建议掺量。

Concrete corrosion is an important factor in the attenuation of its mechanical properties.Underground engineering concrete in Northwest China is often affected by sulfate corrosion,resulting in structural instability or failure to reach the designed service life.This paper took the Zhaoshipan shaft aquifer as the engineering background,the anti-corrosion measures of shaft wall concrete were analyzed,and the micro-morphological differences of concrete mixed with preservatives and the mechanical properties of concrete improved by imitation steel fibers were explored.It was found that the microstructure of concrete specimens mixed with composite preservatives was relatively dense,which could reduce the concentration of sulfate ions that could penetrate into the concrete and refine the pore size of capillary pores;The imitation steel fiber could obviously enhance the strength of the shaft wall concrete,and could significantly improve the mechanical properties of the C50,C60 and C70 shaft wall concrete.According to the water quality characteristics of shaft aquifer,the recommended dosage of composite preservative and steel like fiber for concrete in each section of shaft is given.