The construction of concrete represents very labor-consuming and responsible type of works. It is better to be engaged this summer or in the spring, but it is possible to carry out underpouring and in the period of cold weather – such approach will demand observance of some rules.
Ambient temperature has noticeable impact on concrete hardening process. At 10 degrees above zero the hardening will take place very much and very slowly, and at zero temperature stops at all.
If it happened so that the concrete mix has frozen before has hardened completely, at rise of temperature it is capable to thaw then set of durability proceeds. But the turned-out concrete will not be strong – it can be explained with physical properties of water. When freezing it will increase in volume that will break communication between filler and cement. If necessary to prepare concrete during cold weather it is necessary to protect it from freezing until it stiffens at least half.
It is possible to apply different ways to concrete production in the winter. Applying special additives, the threshold of freezing of concrete can be reduced significantly. Certain fillers together with water allow to create internal stocks of heat by heating of components. Heating is carried out so that temperature of structure was about 30 degrees of heat – no more, otherwise concrete will thicken and will lose plasticity. Water is warmed up up to the temperature +80os. At reaction of water and cement heat will be generated in addition – it will in addition prevent cooling.
To keep heat stock in concrete, it is covered sometimes with materials with good heat-insulating properties. For example, for this purpose sawdust perfectly will approach.
Apply to heating of concrete usually alternating current or steam. Work with steam – process quite labor-consuming, it it is reasonable to use only for large-scale construction. When choosing heating with alternating current armature is used as electrodes. It is necessary to observe temperature no more than +60 degrees at such heating to avoid mix redrying.
At production of concrete in cold weather it is necessary to apply cements only of high-strength brands, to reduce the cement relation to water, to carry out more intensive consolidation and also to enter if necessary various additives.