Mechanical properties of concrete at low and ultra-low temperatures- a review

Abstract

As infrastructure construction advances toward the cold and highland environment, concrete preparation technology and service performance in the cold climate is receiving much attention. The freezing of pore water inside concrete leads to significant changes in its mechanical properties at negative temperatures. Therefore, to ensure the safety of civil engineering structures in cold regions, it is necessary to fully understand the change law and enhancement mechanism of the mechanical properties of concrete and be able to predict mechanical properties at a negative temperature. Since the 1970s, scholars have studied concrete’s negative temperature mechanical properties in different water-content states. This paper presents a comprehensive review of the changes in mechanical properties of concrete at low and ultra-low temperatures and further elucidates the evolution of its compressive strength, tensile strength, flexural strength, elastic modulus, and stress-strain relationship at low temperatures. It was found that the main factors affecting the mechanical properties of concrete at low temperatures were temperature and moisture content. The strength of concrete increases significantly with the decrease in temperature and the increase in moisture content. To better understand and predict the mechanical properties of concrete at low temperatures, the best model was suggested by analyzing the prediction models of different researchers and considering the dispersion of the data. Further, based on the G. Wiedemann pore model, the changes in the internal structure of concrete at low temperatures are described in detail, and the mechanism of its mechanical property enhancement is analyzed.