Complementing the Quantity of Quarry Dust Filler with Lime in Hot Mix Asphalt

Abstract

This study was undertaken to evaluate the effect of quarry dust fillers and hydrated lime on stability and volumetric properties of asphalt. The optimum binder content was determined from asphalt produced with 100% quarry dust regarded as the control mix. The predetermined optimum binder content of the control was used for production of all mixes which includes: 75%granite dust and 25% lime, 50% granite dust and 50% lime, 25% granite dust and 75% lime and 100%granite dust and 0% lime. The aggregates, bitumen and asphalt mix were subjected to various testing. The tests include: sieve analysis test, specific gravity test, aggregate impact and crushing value test, softening point test, water absorption test, flash and fire point test and marshal stability test. Results obtained showed that the optimum binder content was obtained at 6%, the specific gravity of sand, granite dust and granite was 2.67, 2.62 and 2.58 respectively.  Marshal Stability result showed that the stability decreased with increase in lime content from 14.5 kN for the control to 5.3 kN for the mixture containing 100% of filler as hydrated lime. The flow and volumetric properties mostly complied with the specification given by Federal Ministry of Works and Housing, FMWH (1997) apart from the voids filled with bitumen (VTB) for which some values were less than the specified. The study underscores that the use of quarry dust fillers remain a better option as it requires lesser amount of bitumen for better strength and volumetric properties.