State-of-the-Art Report on Control of Cracking in Early Age Concrete

Abstract

AbstractsDurability of concrete structures is seriously compromised by cracking in early age concrete, particularly in high-strength or massive concrete structures. Since early age cracking is influenced by various highly interrelated factors that affect the hydration process and stress/strain development, its behavior is highly complex and no rational methodologies for its control have yet been established. On the other hand, demands for high strength and massive concrete structures in modern cities are ever growing, regardless of the many durability problems. More comprehensive methodologies for the control are therefore essential to ensure sustainability of such structures. This report reviews state-of-the-art research on mechanisms that cause complex cracking phenomena and newly developed methodologies to control early age cracking.

Analysis of Crack Propagation due to Thermal Stress in Concrete Considering Solidified Constitutive Model

“…On the other hand, the mechanical properties of early age concrete rapidly change, particularly in the period when the concrete changes from a liquid to a solid. The key mechanical properties required for analysis at an early age are the modulus of elasticity, the tensile strength, and the properties governing the viscoelastic behavior of the material (Mihashi and Leite 2004). The lack of the time-dependent mechanical properties of concrete especially after cracking is the main problem in the study of early age concrete structural behaviors.…”

Designing Repeatable Self-Healing into Cementitious Materials

“…Cracking will also impair concrete mechanical properties, causing local distress and stiffness reduction in structural members (Vaysburd, Brown, & Bissonnett, 2004). The reduction of service life of concrete infrastructure induced by concrete cracking has led to frequent maintenance and repairs and remains one of the most significant factors limiting the durability of concrete structures (Mehta, 1997;Mihashi & De Leite, 2004). These challenges can be potentially tackled by novel self-healing cementitious materials, which can autogenously regain material transport properties as well as mechanical characteristics after the crack self-healing process.…”

Causes of Early-Age Thermal Cracking of Concrete Foundation Slabs and their Reinforcement to Control the Cracking

“…Under slow cooling conditions, concrete can undergo a 20 K drop in temperature without cracking (Neville, 2011;Shi et al, 2014;Bobko et al, 2015). Early-age cracking occurs when the tensile strain that arises either from restrained thermal contractions or temperature differentials within a concrete section exceeds the actual tensile strain capacity of the concrete (Bamforth, 2007;Carino and Clifton, 1995;Mihashi and Leite, 2004). While such cracks do not typically impact structural integrity, they accelerate deterioration, reduce the serviceability of structures, and may be significant in environmental impact assessments by acting as paths of ingress for ions and/or moisture.…”