The production of high-performance, low-cost warm mix additives (WMa) for matrix asphalt remains a challenge. The pyrolysis method was employed to prepare wax-based WMa using waste polypropylene plastic (WPP) as the raw material in this study. Penetration, softening point, ductility, rotational viscosity, and dynamic shear rheological tests were performed to determine the physical and rheological properties of the modified asphalt. The adhesion properties were characterized using the surface free energy (SFE) method. We proved that the pyrolysis temperature and pressure play a synergistic role in the production of wax-based WMa from WPPs. The product prepared at 380 °C and 1.0 MPa (380-1.0) can improve the penetration of matrix asphalt by 61% and reduce the viscosity (135 °C) of matrix asphalt by 48.6%. Furthermore, the modified asphalt shows favorable elasticity, rutting resistance, and adhesion properties; thus, it serves as a promising WMa for asphalt binders.

Colored polymer anti-skid thin layers are widely used on urban roads to enhance driving safety, improve road aesthetics, and mitigate the urban heat island effect. However, in thin layers constructed by the spreading method, the adhesion of cementitious material to the aggregate is often weak. This leads to early-stage spalling of surface aggregates, thereby reducing the anti-skid performance of the layer. To investigate the factors contributing to spalling, this study examines the embedding behavior of ceramic particles and assesses how the fluidity of the cementitious material and aggregate shape characteristics influence the embedding depth. Using a rotational viscosity test, it is concluded that a cementitious mix ratio of adhesive/powder filler/sand filler = 1:0.5:1 or 1:0.5:1.5 facilitates effective aggregate embedding. Testing the embedding depth of aggregates with the same particle size across different cementitious materials revealed that higher cementitious viscosity results in a reduced aggregate embedding depth. Geometric parameter data for aggregate particles were extensively collected using an image acquisition device, and quantitative analysis identified the shape characteristics influencing the embedding depth. A gray correlation analysis determined that the impact of the shape characteristics on embedding depth follows the order of roundness factor > prism factor > axial coefficient.

The waterborne epoxy resin (WER) colored antiskid thin layer has been widely used in asphalt pavement to improve driving safety. The tectonic depth determines the antiskid performance of aparticle antiskid type thin layer. The spalling of aggregate from a thin layer may reduce the tectonic depth, thus damaging antiskid performance. The spreading process of aggregate on the WER binder surface plays an important role in the spalling behavior of the thin layer. Herein, the influence of spreading processes on the ceramic aggregate spalling behavior on the WER thin layer was investigated based on laboratory experiments. The abrasion and British Pendulum Number (BPN) tests were employed to evaluate the antispalling and antiskid properties of the WER thin layers with different amounts of WER mortar, coverage rates of first-spread aggregate, and spreading orders of coarse/fine aggregates. Moreover, the tectonic depths of the layers before/after the spalling test were also investigated. The results indicated that the optimal dosage of WER mortar is 2.8 kg/m². The WER thin layer exhibited better anti-striping property when coarse ceramic aggregate was spread first. The first-spread coverage rate of the aggregate on the WER surface is 70%. The thin layer exhibited a superior antispalling performance according to the resulting scheme, with a spalling rate of 3.77%. The tectonic depth only decreased from 1.87 to 1.80 mm after the spalling test.