A novel method for tensile testing of very early-age concrete

Early-age cracking can seriously compromise the performance and aesthetics of concrete structures, and is thus an ongoing major concern to the concrete construction industry. More effective control of this form of cracking requires an improved knowledge of concrete properties. In this paper, currently available test methods for complete stress-strain curves of early-age concrete are first briefly reviewed. A new system specifically designed for early-age tensile testing of concrete is then described. The novel use of digital image correlation in this system enables the desired deformation to be reliably captured in a non-contact way – a significant improvement compared to previous studies. The more reliable data to be collected would result in improved knowledge of concrete at early ages, including the tensile strength, Young’s modulus, strain at peak stress, and fracture mechanics characteristics, as well as their interrelationships and development with time. This improved understanding would form a solid basis for more effective control of early-age cracking in concrete