Development of Dilatometer Test Method to Measure Coefficient of Thermal Expansion of Aggregates

Abstract

This paper addresses a user-friendly test method to measure as-received aggregate coefficient of thermal expansion (CoTE) using dilatometery. A dilatometer can accommodate materials of different size, shape, and density and can measure representative CoTE within approximately a 24-h period. The dilatometer test was validated by establishing favorable comparisons between the dilatometer measured CoTE and the CoTE determined by alternative techniques for selected metals, minerals, and aggregates. This method has a great potential to be considered as a laboratory method for measuring the CoTE of aggregate materials. The new dilatometer-based test method can be used by state DOTs and other specifying agencies (1) to determine the CoTE of an aggregate source and to assess the variability of the average CoTE as a measure of quality control and (2) to design mixture proportions for achieving the required concrete CoTE as a function of aggregate CoTE. This test allows for the improvement of the characterization of concrete thermal behavior, as a function of its constituent properties, leading to better performance prediction.