EVALUATION OF ZEOLITE AND PUMICE WASTE AS MINERAL AGGREGATE AND FILLER FOR PRODUCING LIGHTWEIGHT ASPHALT CONCRETE MIXTURES

Abstract

This paper focused on the use of pumice and zeolite waste as aggregate materials for producing lightweight asphalt concrete (AC) mixtures. The samples having pumice, zeolite and limestone aggregate materials were prepared for an optimum bitumen content, optimum Liquid Anti-strip (LAS) additive ratio (0.4, 0.5, 0.6, 0.8, 0.9, 1.0, and 1.1 %), and bitumen type (50/70 and 160/220) determined following the Marshall Mixture design procedure. Then, AC mixes were prepared with limestone used as the coarse aggregate and pumice and zeolite used as fine aggregate, and with limestone used as the fine aggregate and pumice and zeolite used as coarse aggregate. The stability of the mixtures was determined from the Marshall Stability tests. Zeolite and pumice were also used as mineral filler in AC mixtures. Optimum mineral filler ratio and physical properties were determined. In general, pumice and zeolite aggregate mixtures gave lower stability in comparison to limestone aggregate mixtures. These wastes can be applied as very thin wearing layer for increasing friction, to prevent pavement layers from water infiltration, and as overlay with 25-300 mm above old pavement. Because these waste materials have very low weights, they can be used as wearing layer in paving parking areas and non-heavy weight vehicle traffic in roads. The importance of using waste materials and lightweight aggregates is to reduce the environmental impact.