Cold asphalt composition is largely identical to traditional, "hot" asphalt concrete mixtures. However, the production of this coating also involves the use of special substances, thanks to which it can be laid even at sub-zero temperatures. This property gave cold asphalt its common name.
Cold asphalt is produced using liquid bitumen additives, which replace traditional bitumen. This is necessary in order, so that when the temperature drops, the viscosity of the mixture does not decrease, like the regular composition, and increased. Besides, the coating contains additives, which form a protective layer, preventing asphalt from hardening prematurely. Thanks to this layer, cold asphalt can be stored for a long time. In air, the protection is quickly destroyed, and the coating hardens to the desired state, strength is not inferior to ordinary asphalt. This process goes very quickly: The road can be used for heavy traffic immediately after laying the new surface. Thus, cold asphalt is indispensable for urgent repairs.
Production of cold asphalt, usually, are engaged in enterprises for the production of conventional asphalt concrete pavement, however, special units are used. Components of the coating – crushed stone, bitumen and additives. The condition of the crushed stone is carefully monitored: it is thoroughly sifted before use, warms up to 100 degrees Celsius (But no more). To ensure that the mixture is of the highest quality, manufacturers pay equal attention to the condition of all its components.
When producing cold asphalt, the percentage of bitumen is approximately 4,3% from the mass of crushed stone. After mixing the crushed stone and bitumen mass, an admixture is added, whose properties make it possible to extend service life and, what is not less important, material storage. The total mass of the impurity is approximately one third of the mass of bitumen. It is not added to the bitumen line, and into the already mixed asphalt. After this, additional mixing is carried out (from 20 to 23 seconds), after which the mixture is ready for use: it can be used even immediately after preparation.
Cold asphalt can be stored for many years and still be always ready for use.. Of course, storage rules must be followed: use sealed bags, since the entry of air can cause the material to harden and, to a large extent, loss of operational properties.