Preparation Methods and Performance of Modified Asphalt Using Rubber–Plastic Alloy and Its Compounds

Abstract

In this study, two types of modified asphalts were prepared via two different approaches, using as modifiers waste rubber and plastic and other raw materials. One approach followed a two-step mechanism of melting-blending thermal plastic elastomers (TPE) with the raw materials, which included waste rubber powder, plastic, styrene-butadiene-styrene, and plasticizer. The second approach involved the direct mixing of asphalt with the mixture of raw materials in a single step. From a comparison of the microperformance and macroperformance indices of the modified asphalts, it was found that the high-temperature preparation for the TPE polymer alloy–modified asphalt resulted in the relatively high aging of the modifying material, leading to poor performance. The asphalt prepared via the compound-modified approach exhibited better performance indices and distribution of the modifier in the base asphalt. The modified asphalt samples were characterized by atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR) and fluorescence microscopy (FM) techniques, which helped in the interpretation of the experimental data, textural characterization, and preparation techniques (melt-blending and direct mixing). The present approach could be deemed helpful in improving and optimizing the existing methods of rubber–plastic alloy-modified asphalt preparation, the specific quantities of the modifiers, and the modification parameters used in the asphalt-modifying industries, in order to achieve the best performance that meets market demands.