Utilizing polymers for asphalt concrete (AC) mixture modification has many drawbacks that hinder its wide implementations for roadway construction. Recently, research on employing complementary materials, such as nanomaterials, to balance negative impacts of polymers while enhancing the AC mixture’s performance has received great attention. This study aimed to investigate the effect of incorporating nanoclay (NC) particles on the performance of a high-density polyethylene (HDPE)-modified AC mixture. A 60/70 asphalt binder was first modified with HDPE, and then NC particles were gradually added at a concentration of 1–4% by weight of the asphalt binder. The binders’ physical characteristics, storage stability, and chemical change were scrutinized. AC mixture performance, including pseudo-stiffness, moisture damage resistance, stripping susceptibility, and rutting tendency, was investigated. A statistical analysis on the experimental results was conducted using Kruskal–Wallis and Dunn tests. Test results showed that employing NC/HDPE significantly increased penetration index and thereby enhanced binder temperature sensitivity. Moreover, it prevented oxidation action and separation and, therefore, enhanced binder storage stability. Furthermore, incorporating NC amplified pseudo-stiffness and significantly improved resistance against moisture damage and stripping of HDPE-modified mixtures. Moreover, it improved both elastic (recoverable) and plastic (unrecoverable) deformations of mixtures. The most satisfactory results were attained when incorporating 3% of NC.

This study investigates the potential of two bitumen modifiers, high-density polyethylene (HDPE) and nano clay (NC), to enhance the rutting resistance of asphalt mixture. Four HDPE asphalt binders were prepared by mixing the HDPE at percentages of 2%, 4%, 6%, and 8% with the virgin binder, while four NC asphalt binders were produced by mixing the NC at percentages of 1%, 2%, 3%, and 4%. The consistency and flow of virgin binder, HDPE binders, and NC binders were evaluated by penetration, softening point, and viscosity tests. The results show a gradual increment in the binder stiffness by increasing the percentage of both modifiers. The static creep test was conducted at a temperature of 40 °C to evaluate the rutting resistance. The results confirm that both modifiers can greatly improve the rutting resistance of the asphalt mixture, where 8% HDPE and 3% NC modifications reduce the strains provoked in the asphalt mixture under loading by about 50%. According to the correlation analysis, the mixture rutting performance is highly attributed to the binder stiffness, where the lower the penetration value of the asphalt binder, the lower the strains in the asphalt mixture and the higher the stiffness modulus of the asphalt mixture.

Recently, nanomaterials have been widely used to improve the properties of asphalt binders due to their unique properties. This research aims to evaluate the performance of nano-modified binders with two different types of nanomaterials, which are Nano-Silica (NS) and Nano-Clay (NC). Each of them was added to a 60/70 penetration grade bitumen at concentrations ranging from 1% to 4% by asphalt binder weight using a high shear mixer at a speed of 4000 rpm and a mixing temperature of 145 °C for 60 minutes. A number of basic tests were carried out on the binders, such as penetration grade, softening point, rotational viscosity, and stability storage tests. Moreover, Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FTIR) tests were utilized to ensure the quality of the mixing process and investigate the modified binder's internal composition. Furthermore, an additional laboratory study was carried out to characterize the performance properties of the corresponding asphalt concrete (AC) mixtures based on the Marshall stability, indirect tensile strength, moisture susceptibility, double-punch, and static creep tests. Based on the experimental results, the best performance was attained when incorporating 3-4% nanoparticles with a neat asphalt binder. In general, the addition of NS or NC particles positively affected the asphalt binder and AC mixture in terms of stability, debonding, moisture damage, and rutting. However, NC was more effective compared to NS and can be used to build sturdy pavements

Flexible pavements are susceptible to the damaging effects of moisture, causing various kinds of problemes for asphalt such as stripping. That reduces the durability and serviceability life of pavements and consequently increases the construction and maintenance cost. The aim of this research is to study the moisture sensitivity of the hot asphalt mixture with high-density polyethylene as an asphalt binder modifier. Asphalt 60/70 was mixed with several concentrations of high-density polyethylene (HDPE) ranging from 2% to 8% by bitumen weight using a high shear mixer at a temperature of 180 0C and a speed of 4000 rpm for 60 minutes. Penetration depth, softening point, rotational viscosity (RV), and scanning electron microscopy (SEM) tests were performed on both the conventional and HDPE-modified binders. Asphalt mixtures were designed according to the Egyptian specifications using the Marshall method. Conventional and HDPE-modified asphalt mixtures' moisture susceptibilities were evaluated through indirect tensile strength (IDT) and loss of stability tests. Results of scanning electron microscopy (SEM) showed that HDPE was homogeneously dispersed through the binder with no polymer cluster formations. Testing results revealed that adding high-density polyethylene at a concentration of 4% gives superior performance in most tests. Adding HDPE significantly improved the properties of asphalt binder, increased the hardness of the asphalt mixture and reduced the effect of moisture damage.