Study on Mechanical Properties of Aerogel Concrete at High Temperatures

Abstract

In this paper, uniaxial compression tests were carried out on aerogel concrete at room temperature and after exposure to high temperatures. The influence of different aerogel contents on the degradation law of mechanical properties of concrete at room temperature and high temperature was investigated. The results show that at room temperature, the strength of concrete first decreases, then increases, and then decreases with the increase of aerogel content. When the aerogel content is controlled at 5%–15%, the strength reduction of the specimens is relatively gentle. After high-temperature treatment, the compressive strength of aerogel concrete exhibits an obvious temperature effect. Before 500℃, the strength increases slightly and then decreases gradually, indicating that hydration products are still formed and strength develops to a certain extent inside the concrete at this stage. However, the microcracks induced by temperature rise propagate continuously and gradually offset the strengthening effect caused by hydration. After 500℃, the compressive strength drops sharply, revealing that high temperature significantly aggravates the internal structural damage of concrete. When the temperature rises to 900℃, the strength loss can reach up to 0.886, and the specimens basically lose their bearing capacity. This reflects that continuous high temperature has caused serious damage to the internal structure of concrete, making it difficult to maintain the original mechanical performance.