CONCRETES ON SECONDARY CRUSHED STONE AS A PROMISING MATERIAL FOR THE RIGID PAVEMENT BASE

In the course of research, the efficiency of application of plasticizers of different type in concretes for bases of highways on secondary crushed stone is defined. In studies of concrete compositions, the type of crushed stone, secondary or granite, changed, which allowed to compare the properties of concrete on secondary crushed stone with the properties of concrete of similar composition on granite crushed stone. In addition, the type of sand changed: Bilyaevsky or Voznesenski quarry. As modifiers used additive lignosulfonate or superplasticizer polycarboxylate type MC-PowerFlow 3200. All concrete mixtures had equal mobility P2, which was provided by variation W/C (water-cement ratio). It was found that the concrete on the secondary crushed stone is characterized by a significantly higher W/C mixture due to greater porosity and damage to the surface of the coarse aggregate. The average density of concrete on secondary crushed stone is 4.2-4.4% lower compared to the average density of concrete on granite crushed stone. The average density of concrete on the larger sand of the Voznesenski quarry is 25-30 kg/m3 higher than the average density of concrete on similar gravel and finer