Properties of Monolithic Cement Concrete, Hardening at Temperatures Close to Zero

Abstract

One of the main problems of hardening monolithic cement concrete, especially in the conditions of restoration and reconstruction of various objects, is the hardening of concrete in conditions of negative temperatures. Winter concreting technologies are divided into two main methods: the thermos method, in which the temperature of the environment in which the concrete hardens, must be above zero degrees Celsius, or the use of antifreeze additives. In the last case, it is advisable to introduce antifreeze chemical additives into the concrete composition, which lower the freezing temperature of water in concrete. However, previously conducted studies are known that show that even in the case of early freezing of concrete, its quality remains high. In this case, it is necessary that the beginning of setting of the cement paste occurs before the concrete can freeze. In addition, it has been suggested that concrete hardening at low temperatures can occur without using the thermos method. The article presents the results of the influence of hardening temperature on the setting time of cement paste. It is shown how hardening conditions affect on the strength and frost resistance of concrete.