Evaluation of the effect of enrichment of slag aggregate for pavement subbase by grains density on its physical and mechanical characteristics

Abstract

The article presents the results of a laboratory evaluation of the influence of the enrichment of the slag aggregate (size 20–40 mm) for road construction, obtained from the air-cooled blast furnace slag, on the grains density, on its water absorption, freeze-thaw resistance and resistance to crushing. The results of quantitative and qualitative evaluation of the obtained empirical dependences, performed using the methods of correlation analysis and approximation, are presented. Enrichment of the slag aggregate in terms of grains density makes it possible to reduce its water absorption from 4.9-6.8% to 2.19–3.13%, increase the number of repeated freeze-thaw cycles maintained without significant destruction, from 150 to 300–400, and reduce crushing value from 30-31% to 20–21%. The resulting approximation equations make it possible to predict the change in physical-mechanical characteristics with further enrichment of the slag aggregate in terms of grains density. Laboratory tests showed that the slag aggregate, pre-enriched in grain density, when used as aggregate for pavement subbase operated in continental climates with frequent natural repetition of freeze-thaw cycles, will resist the temperature fluctuations much more effectively than the high-porosity slag aggregate used without enrichment.