Laboratory study on the asphalt mixture performance by nano-CaCO3 and basalt fiber

Due to rapid changes in weather conditions and increased traffic loads, asphalt pavements have become more susceptible to distress such as rutting, fatigue cracks, and potholes. Therefore, significant attention has been focused on improving the performance of these pavements through various modifications. The objectives of this study are to enhance the overall performance of the asphalt mixture and improve its ability to resist traffic loads at both low and high temperatures simultaneously by using double additives from basalt fiber and nano-CaCO 3 . The study applied Marshall Stability, Wheel Track Test (WTT), Indirect Tensile Strength (ITS), and Marshall Immersion (MI) tests to assess the performance of the modified mixes. Additionally, the physical properties were examined using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. Four asphalt mixtures were tested: the first was a control asphalt mix (CAM) to determine the optimum bitumen content (OBC); the second was nano-CaCO 3 modified asphalt mix (NCAM) with 2%, 4%, 6%, and 8% of the bitumen weight; the third was basalt fiber modified asphalt mix (BFAM) with 0.25%, 0.5%, 0.75%, and 1% of the asphalt mix weight; and the fourth mixture contained 5.5% bitumen and optimum ratios of nano-CaCO 3 and basalt fibers (NCBFAM). The results showed that the addition of 8% nano-CaCO 3 led to significant improvements of 53.97% in rutting resistance, 22.7% in low temperature, and 12.5% in durability (RMS) compared to the control mix (CAM). The addition of 0.5% basalt fibers improved rutting resistance by 32.54%, ITS by 7.62%, and durability by 6.3%. However, the combination of 8% nano-CaCO 3 and 0.5% basalt fibers (NCBFAM) resulted in the most substantial improvements, with increases of 46.83% in rutting resistance, 18.94% in low temperature, and 10.26% in durability compared to the conventional mix. These findings demonstrate that the combined addition of nano-CaCO 3 and basalt fibers significantly enhances the Marshall properties, high and low temperature, and durability of the asphalt mix.