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

Abstract

The Temperature-Stress Testing Machine (TSTM) is a powerful test setup that allows to holistically study several key performance characteristics of concrete from very early ages. In this paper, key features of existing TSTMs are first reviewed, together with their remaining drawbacks. On that basis, the paper provides insights into the detailed design of the new TSTM at The University of Queensland (UQ), including: efficient heat transfer and thermal regulating system, advanced deformation control and capturing devices and automatic control algorithm. Such detailed information on the design and performance of TSTM is aimed to address the current lack of such critical information, facilitating further improvements of TSTMs. Evidence demonstrating the reliability and repeatability of the new TSTM is also presented. Finally, to further demonstrate its capability, the paper presents several aspects of an on-going study at UQ utilising the new TSTM to study autogenous shrinkage under realistic temperature histories, thermal coefficients of expansion and contraction, tensile creep and zero-stress temperature, 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.