Influence of Water Content on Total Strain of Super High-Strength Concrete Under Elevated Temperature

Abstract

The purpose of the present study is to present an accurate constitutive model of the concrete under elevated temperature. The present study is an experimental study on the influence of evaporable water in concrete, the water/binder (W/B) ratio, and the loading level on the thermal strain and the total strain of high-strength concrete up to 700 °C. The cylindrical specimens were preconditioned by air-drying or oven-drying at 105 °C. Expansion was larger for total strains in oven-dried specimens than those in air-dried specimens between 100 and 500 °C at stress levels from 0 to 30 %. The influence of W/B ratio was unclear. The coefficient of load-induced thermal strain (LITS), a measure of strain identified by subtracting the thermal strain from the total strain, and thermal expansion coefficient were higher for oven-dried specimens than for air-dried specimens below 200 °C. When the stress level was increased, the differences for both were more evident. The formularization of the total strain was performed in accordance with LITS model. The calculated values indicated reasonable agreement with the experimental values relatively for air-dried specimens at load levels of 30 % and 50 %.