Performance characterization of plain and CFRP-bonded concrete subjected to sulfuric acid

• Published in: Materials & design Vol. 197; p. 109176
• Main Authors: Ji, Yongcheng, Kim, Yail J., Jia, Yanmin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2021; Elsevier
• Subjects: Carbon fiber reinforced polymer (CFRP); Concrete; Durability; Performance characterization; Sulfuric acid; Performance characterization; Durability; Concrete; Carbon fiber reinforced polymer (CFRP); Sulfuric acid
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2020.109176

This paper presents the durability performance of concrete subjected to sulfuric acid. Accelerated conditioning is conducted at a 5% concentration employing concrete blocks bonded with carbon fiber reinforced polymer (CFRP) sheets, which are used for rehabilitating impaired structural members, and plain concrete blocks. After deteriorating the specimens for up to 9 weeks, various physical and mechanical tests are carried out such as digital microscopy, resonance frequency, porosity, thermogravimetry, and flexural loading. The initial uptake of sulfuric acid raises the mass of the concrete by 5.9%, on average; however, with the increased exposure period, the mass decreases by 19.8% because of the dissolved cement paste and enlarged pores. The presence of a CFRP layer partially hinders the ingress of sulfuric acid and improves the integrity of the concrete. Irreversible damage in the conditioned specimens reduces their resonant frequency and dynamic modulus as low as 20.3% and 49.0%, respectively. According to thermogravimetric results, the acid conditioning changes the microstructure of the concrete. While the flexural capacity of the blocks rises over 409% after CFRP-bonding, the level of uncertainty increases owing to the irregular deterioration of the CFRP-concrete interface. Furthermore, the capacity reduction and flexural stiffness of the specimens, as well as the debonding characteristics of CFRP, are dependent upon exposure period. A probability-based analytical model is formulated to complement the experimental findings, including the quantification of hazard and reliability. By comprehending the unexplored degradation mechanisms of concrete with and without CFRP-bonding under the sulfuric acid environment, a link is established between material-level damage and sustainable rehabilitation systems. [Display omitted] •The presence of a composite layer partially hinders the ingress of sulfuric acid and improves the integrity of concrete.•Irregular deterioration raises uncertainty in the composite-concrete interface.•The hazard function of the conditioned specimens increases, while the composite enhances the reliability of the system.