Durability of reactive powder concrete of drilling shaft and triaxial compression damage constitutive model under composite salt erosion. (15th December 2022)

• Record Type: Journal Article
• Authors: Fang, Yu; Yao, Zhishu; Li, Xinwei; Xu, Yongjie; Huang, Xianwen
• Is Part Of: Journal of building engineering. Volume 62(2022)
• Publication Date: 2022-12-15
• Subjects: Drilling shaft lining -- Reactive powder concrete -- Durability -- Composite salt erosion -- Damage constitutive model; Building -- Periodicals; 690.05
• DOI: 10.1016/j.jobe.2022.105395
• Languages: English
• ISSNs: 2352-7102

Abstract

Abstract: This study aimed to improve the bearing capacity of the drilling shaft and the durability of resistance to composite salt erosion in water-rich and weakly consolidated formations. Hence, reactive powder concrete (RPC) is proposed as the construction material for the drilling shaft. RPC macroscopic mechanical behavior, mesoscopic pore structure, and microscopic characteristics as well as a triaxial compression damage constitutive model under a composite salt erosion environment were studied and analyzed. First, the accelerated corrosion test method was used to compare the macroscopic mechanical properties and apparent morphology deterioration of C70 high-strength and high-performance concrete with those of RPC140 and RPC 110 (based on the same mix ratio) prepared by autoclave curing and standard curing, respectively, under composite salt solutions of three concentrations. Then, mercury intrusion porosimetry and scanning electron microscopy analyses were used to determine the pore structure changes and micro hydration characteristics of the concrete specimens before and after salt erosion. The results showed that the high concentration of the composite salt aggravated the deterioration of the concrete performance, and the mass loss rate and compressive strength corrosion resistance coefficient of the concrete changed dynamically as the age of erosion increased. The macro-mechanical properties and microstructure of RPC140 after autoclave curing were the best and showed the strongest resistance capacity to composite salt erosion, compared with those of C70 and RPC110 of standard curing. Finally, according to Weibull's statistical damage theory, a triaxial compression damage constitutive model of concrete under composite salt erosion was established and verified by experiments. Highlights: Differences in composite salt resistance of C70 HSHPC, standard-curing RPC110, and autoclave-curing RPC140 were investigated. Pore structure and hydration product of composite-salt-corroded concrete were investigated. Triaxial compressive damage constitutive model of concrete under composite salt erosion was proposed.