Enhancing the Sustainability of Asphalt Concrete by Implementation of Additives

Abstract

The sustainability of asphalt concrete pavement could be achieved after proper selection of the constitute materials. Additives can furnish the required enhancement of the pavement. In the present work, coal fly ash class F and silica fumes were implicated in the asphalt concrete mixture as partial substitute of mineral filler. Asphalt concrete slab samples have been prepared in the laboratory using roller compaction and optimum percentage of asphalt binder. Beam specimens of asphalt concrete have been extracted from the prepared slab samples and subjected to testing for fatigue life using three constant microstrain levels using the dynamic flexural bending beam test. It was noticed that implication of additives exhibit decline in the fatigue life of asphalt concrete by (58.3, and 50) % when silica fumes and fly ash were incorporated in asphalt concrete mixture respectively when compared with that of the control mixture. The resistance of the fly ash treated asphalt concrete mixture to flexural stresses increases by (51.2, and 118) % at the peak value when the constant strain level increases from 250 to 400 and 750 respectively. However, the resistance of the silica fumes treated asphalt concrete mixture to flexural stresses increases by (60, and 600) % at the peak value when the constant strain level increases from 250 to 400 and 750 respectively. It was concluded that asphalt concrete mixture, treated with silica fumes additives, exhibit 41.6 % increment in the resistance to flexural stresses as compared with fly ash treated or control mixtures. Silica fumes additive is recommended to enhance the sustainability of asphalt concrete.