Search Results for Aso Faiz Talabani

Abstract

This study investigates the effect of partially replacing conventional mineral limestone dust (LD) filler with nano-calcium carbonate (NCC) and nano-silica (NS) on the moisture damage resistance and mechanical strength of hot mix asphalt (HMA). Asphalt mastic samples were prepared using a 40/50 penetration grade asphalt binder, with NCC and NS incorporated at 0%, 5%, 10%, 15%, and 20% by weight of total filler. A constant filler-to-binder ratio of 0.72 was maintained across all mixtures. Performance was evaluated through indirect tensile strength (ITS), tensile strength ratio (TSR), compressive strength, and index of retained strength (IRS) tests. Results indicated resistance to moisture damage can be significantly enhanced by partially substituting NCC and NS for the LD filler. The optimum ITS was observed at 10% nano-filler content, showing a 33.0% increase for NCC and a 33.2% increase for NS mixtures compared to the control mixture. At same replacement level, TSR reached 91% for NCC and 92% for NS mixtures. Compressive strength improved by 4.27% and 5.95% for NCC and NS mixtures, respectively, at 20% replacement, while IRS improved to 95% for NCC and 94% for NS mixtures at the same level of replacement. According to Field Emission Scanning Electron Microscopy (FESEM), using NS and NCC nano-fillers, significantly enhances particle dispersion and reduced air voids compared to mixtures without nano fillers. Overall, mixtures with nano filler improved matrix density and filler–binder cohesion, also achieved the most compact structure, leading to better durability and moisture resistance.