Pavement types

Highways are divided into two main types according to the surface structure : non-rigid (asphalt concrete) and rigid (cement concrete). Find out more site. Asphalt concrete (or simply - asphalt) is a mixture of stone aggregates, a binder - bitumen and modifier additives. When viscous bitumen is used to make the material, the mixture is called hot; if liquid bitumen - cold. Although in both cases, asphalt concrete is prepared in a hot state (130-180°C). But in the second - they are laid at a temperature of about 30 ° C. For density and evenness, the asphalt pavement is compacted with heavy rollers. Cement concrete (concrete) is formed from the hardening of aggregates with a binder. But as the latter, cement with various additives (plasticizers, air-entraining additives) is used. Water is added to the mixture. An air-entraining additive is necessary to create micropores in concrete in order to increase its frost resistance. The pores allow the water contained in the concrete mix to expand when frozen without damaging the material. The superplasticizer significantly reduces the amount of water in concrete, increases the mobility and plasticity of the material, increasing the bending strength of the concrete mixture.