Experimental Investigation to Improve the Thermomechanical Response of Concrete Samples Subjected to Coefficient of Thermal Expansion Testing

Thermomechanical response of coefficient of thermal expansion (CTE) test samples plays an important role in the consistency of CTE test results. Saturated concrete samples while subjected to heating and cooling develop internal pressure due to the dissimilar thermal expansion/contraction of solid and liquid phases. This fundamental property of saturated concrete has not yet been considered as a criterion to improve the CTE test procedure. This paper presents an experimental investigation to reduce the effect of internal water pressure on the measured CTE results. The paper experimentally evaluates three techniques—preconditioning the concrete samples by heating and cooling cycles prior to CTE test, precracking concrete samples, and reducing the rate of temperature change. Preconditioning concrete samples by heating and cooling cycles prior to CTE testing noticeably improves the consistency of CTE test results. Decreasing the rate of temperature change also improves the consistency of the test results but significantly increases the test duration. Precracking shows improvement in a few test parameters, but the results are unreliable for in situ concrete due to the adverse effect of increased porosity.