腐蚀介质下粉煤灰混凝土宏微观性能的时变损伤

以2 mol/L NH4 Cl溶液为腐蚀介质,研究全浸泡条件下粉煤灰混凝土的耐蚀性能.溶蚀前,对粉煤灰混凝土进行气孔结构测试分析,研究溶蚀后的抗压强度损失以及溶蚀深度的变化幅度及变化规律,并采用核磁共振、场发射扫描电镜从机理上探讨不同粉煤灰掺量(0％、15％、30％、45％)混凝土溶蚀后的组织结构和孔隙的分布情况.研究...

Time-varying Damage of Macro-and-micro Properties of Fly Ash Concrete in Corrosive Media

The corrosion resistance of fly ash concrete fully soaked in 2 mol/L NH₄Cl solution as corrosive medium was studied in this paper. Before dissolution, the stomatal structure of fly ash concrete was tested and analyzed. The loss of compressive strength together with the change amplitude and change law of dissolution depth after the dissolution was investigated. Moreover, the structure and pore distribution of concrete after dissolution with different amounts of fly ash (0%, 15%, 30%, 45%) were examined via nuclear magnetic resonance and field emission scanning electron microscopy. Research results manifested that fly ash refined the internal pores of concrete, reduced pore connectivity and improved pore size distribution, which effectively enhanced the structural safety and corrosion resistance of concrete in water environment. Compared with ordinary concrete dissolution area, fly ash concrete dissolution area had ettringite crystals generated inside, indicating that the formation of ettringite can reduce corrosion damage.