Temperature-stress testing machine - A state-of-the-art design and its unique applications in concrete research

The Temperature-Stress Testing Machine (TSTM) is a unique experimental setup that allows to study a number of fundamental properties of concrete from very early ages, thereby enabling proper assessment of cracking risk. Such critical role necessitates new constructions of TSTM with further developments to address major drawbacks in its current versions. However, there have been very limited reference sources with sufficient information to facilitate the purpose. Based on a newly-designed and built TSTM developed at The University of Queensland (UQ), Australia, the paper provides insights into its detailed design and state-of-the-art improvements. Especially, for the first time, integrated control processes for every sub-system/component are also explained in detail to supplement the lack in current reference sources and encourage future developments. Also, in this paper, verification steps to confirm the reliability and repeatability of the machine are discussed. Finally, to illustrate its practicability and capability in concrete research, the last section briefs several aspects of an on-going study at UQ utilising the TSTM to study autogenous shrinkage under various temperature histories, thermal coefficients of expansion and contraction, tensile creep, zero-stress temperature and Young's modulus, as well as their combined effects on early-age cracking risk of concrete structures. The resulting improved knowledge is expected to lead to better guidelines for effective crack control that will enable significant cost savings and more sustainable construction industry