WASTEWATER SLUDGE ASH IN THE PRODUCTION OF A NOVEL COLD MIX ASPHALT (CMA): DURABILITY, AGING AND TOXICITY CHARACTERISTICS

Abstract

New Sustainable with no CO2 emission cold mix asphalt (CMA) for road and highways surfacing is successfully developed from wastewater sludge ash normally sent to landfills. The Paper reports; durability in terms of water sensitivity, aging and contamination levels of heavy metals of the new developed novel CMA containing upgraded fly and bottom ash secondary cementitious materials from United Utilities fly and bottom ashes. Road engineers currently restricted the use of conventional CMA containing conventional limestone fillers (LF) for use in walkways and light trafficked roads only, as these mixtures needs from 2 to 24 months for curing. Conventional CMA mixtures also have high voidage contents and thus low traffic bearing capacity. The durability of these mixes is low especially in the UK and European countries where the climate is predominantly wet and cold.In Germany and France, ordinary Portland cement (OPC) replaced the filler used in traditional CMA. Although this allows the new CMA to be used in roads for light and heavy trafficked loads. The materials are not environmentally friendly, as one tone of cement releases approximately one tone of CO2 emission during their manufacturing process. The results of the new developed CMA are satisfying the British and European codes of practices requirements. The new novel mixtures are also; highly cost-effective compared with the use of Hot Mix Asphalt (HMA), has no CO2 emission during mixing construction, and has no health and safety issues compared with the HMA manufacturing and application process.