| Popis: |
As a rule, motor roads are composed of the subgrade and the road dressing. Road dressing is composed of the road pavement, road base and the bottoming. Road dressing may be non-rigid (or made of coarse asphalt concrete, fine asphalt concrete, tar concrete, rubble or gravel treated by binding agents, etc.) and rigid (asphalt concrete road pavements resting on the road base made of cement concrete, or prefabricated pavements made of reinforced concrete and ferrocement slabs, monolithic cement concrete pavements). Cement concrete roads are five to six times more durable than asphalt concrete roads; their service life may exceed 50 years. They are resistant to environmental attacks; they ensure excellent grip of the wheel, and they are dust-free. Their road pavement is resistant to wear (0.1 mm per year); its thickness does not exceed 16-22 mm. Therefore, effective concrete road pavements require self-compacting though non-segregating concrete mixtures to comply with the pre-set values of their properties, namely, bending and compressive strength, corrosion resistance, freeze resistance, etc. Acting in cooperation with Department of Technology of Binders and Concretes of MSUCE, NIIMosstroy developed and examined a self-compacting cast concrete mixture designated for durable monolithic road pavements. The composition in question was generated by adding a multi-component modifier into the mix. The modifier was composed of a hyperplasticiser, active (structureless) fine and crystalline silica, and a concrete hardening control agent. |
