Bond durability between BFRP bars and seawater coral aggregate concrete under seawater corrosion environments. (23rd May 2023)

• Record Type: Journal Article
• Authors: Zhang, Bai; Zhu, Hong; Chen, Jun
• Is Part Of: Construction & building materials. Volume 379(2023)
• Publication Date: 2023-05-23
• Subjects: Durability -- Bond characteristics -- BFRP bars -- Coral aggregate concrete -- Seawater environments; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2023.131274
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Bond durability between BFRP bars and seawater coral aggregate concrete (CAC) under seawater environments was evaluated. Seawater environment exposure weakened the bond strength of the specimens but strengthened their bond stiffness. Increasing the exposure temperature accelerated the deterioration in bond characteristics. The deterioration in the bond strength was related to the degradation in material strength. Abstract: The combination of fiber-reinforced polymer (FRP) composites with seawater coral aggregate concrete (CAC) in offshore construction contributes to reduced construction costs and avoids the corrosion problems related to steel-reinforced concrete structures. However, the durability for FRP-reinforced CAC members during service in marine environments is not well understood, which greatly hinders their application in offshore construction. In this paper, accelerated aging tests were employed for investigating the bond performance between the basalt-FRP (BFRP) bars and the CAC under seawater drying-wetting cycle and immersion environments. The effects of various exposure temperatures and exposure times on bond characteristics were considered, and scanning electron microscopy (SEM) was adopted to characterize microstructure changes at the cross-section of BFRP bars subjected to seawater exposure environments. The experimental results revealed that after being exposed to seawater corrosion conditions, the slope in the rising stage of the curves (i.e., initial bond stiffness) appeared to increase somewhat due to the hygroscopic expansion effect of the FRP bars, but the bond strength and its corresponding slip value demonstrated a gradual decrease. After being subjected to seawater drying-wetting cycle conditions at 45 °C and 60 °C for 12 months, the bond strength of BFRP bars in CAC declined by approximately 6.5 % and 12.0 %, respectively. This deterioration in the bond strength was related to the degradations in the mechanical properties of the FRP bars and the CAC, as well as the interfacial performance between the FRP bars and the CAC.