Influence of mineral composition of siliceous rock on its volume change

A method for predicting volume changes of aggregate during variations in humidity and temperature was studied. Siliceous rock aggregates commercially available in Japan were sampled from various regions and subjected to XRD (X-ray diffraction) analysis, thermal analysis, and volume change experiments. Drying shrinkage strain and the thermal expansion coefficient of the aggregates were found to be related to their mineral composition and bound water content. Experiments confirmed that drying shrinkage was correlated with the chlorite and bound water content of the aggregate, and that thermal expansion coefficients were correlated with the aggregate's quartz content.