PERFORMANCE EVALUATION OF HOT MIX ASPHALT (HMA) BY USING NANO SILICA AND FLY ASH

Abstract

Roads are an essential requirement for human civilization, and a majority of roads worldwide are constructed using flexible pavement. However, these roads are prone to damage, such as cracking, potholes, and rutting, primarily due to factors like heavy traffic, high loads, and significant temperature fluctuations. Furthermore, in our country, there is a substantial production of fly ash, which directly contributes to environmental pollution. Recycling waste materials while building pavement gives significant cost savings over buying new materials and also reducing the amount of waste that needs to be disposed of.

We carried out research to determine the effects of utilizing Nano silica & Fly ash as mineral fillers on both the Marshall Properties & flow properties of Hot Mix Asphalt (HMA). We added nano silica at a percentage of the total binder content and fly ash at a percentage of the filler content. Different combinations with binder levels ranging from 3.5% to 5% were examined, including 4% fly ash with 2% nano silica, 8% fly ash & 4% nano silica, & 12% fly ash & 6% nano silica.

The research findings indicated that the most favorable outcome was achieved with a combination of 8% fly ash and 4% nano silica at a binder content of 4.5%. Maximum stability, comparatively good flow values, a low amount of air voids, and the highest amounts of VMA (voids in mineral aggregate) & VFA (voids filled with asphalt) were all displayed by this particular combination. These findings demonstrate the value of adding fly ash & nano silica to the asphalt mixture and their potential to improve the functionality and longevity of flexible pavement.

By utilizing waste materials like fly ash, we can contribute to sustainable construction practices while mitigating environmental pollution. The outcomes of this study provide valuable insights for the development of cost-effective and eco-friendly pavement construction techniques.