A review of mechanical properties of deteriorated concrete due to delayed ettringite formation and its influence on the structural behavior of reinforced concrete members

Abstract

Reinforced concrete (RC) members are subject to map cracking owing to the delayed ettringite formation (DEF) by excessive core temperature during the first few days of hydration. Studies on the mechanical properties of concrete with DEF expansion have been conducted to identify the variation in moduli and strength of the material. This paper provides a comprehensive review of the mechanical properties of plain concrete with DEF expansion to examine the degradation characteristics compared to the experimental conditions. The dynamic moduli, static moduli, and compressive strength of the plain concrete decreased up to 60%, 85%, and 65%, respectively, owing to large swelling, where the damage process showed colossal expansion. The reduction amount depends on the aggregate-to-cement ratio, chemical composition of the cement, aggregate type, water-to-cement ratio, and the mix. The static moduli is more sensitive to expansion in the initial expansion stage than other mechanical properties. The structural performance of DEF-affected RC members was also investigated, reviewing the relevant studies to include the structural performance of alkali-silica reaction (ASR) affected structures. The structural performance cannot be appraised using the mechanical properties of plain concrete. It was indicated that the DEF expansion of concrete core can be significantly confined by surrounding reinforcement in RC members. This inhibits the reduction in mechanical properties of concrete and results in maintaining the load-carrying capacity of RC members. Chemical prestress developed in concrete due to the swelling restraint by reinforcement, and anisotropic damage improves the stiffness of the RC members.