Design of Cold-Mixed High-Toughness Ultra-Thin Asphalt Layer towards Sustainable Pavement Construction

Abstract

Ultra-thin asphalt overlay has become the mainstream measure of road preventive maintenance due to its good economic benefits and road performance. However, hot mix asphalt concrete technology is widely used at present, which is not the most ideal way to promote energy saving and emission reduction in the field of road maintenance. At the same time, the ultra-thin friction course based on cold mix technology, such as slurry seal layer, micro-surface, and other technologies, are still far behind the hot mix friction course in terms of crack resistance. In this research, by establishing an integrated design of materials and structures, a cold paving technology called “high-toughness cold-mixed ultra-thin pavement (HCUP)” is proposed. The high-viscosity emulsified bitumen prepared by using high-viscosity and high-elasticity modified bitumen is used as the binder and sticky layer of HCUP. The thickness of HCUP is 0.8–2.0 cm, the typical thickness is 1.2 cm, and the nominal maximum size of the coarse aggregate is 8 mm. Indoor tests show that HCUP-8 has water stability, anti-skid performance, high temperature performance, peeling resistance, and crack resistance that are not weaker than traditional hot-mixed ultra-thin wear layers such as AC-10, Novachip, and GT-8. At the same time, the test road paving further proved that HCUP-8 has excellent road performance with a view to providing new ideas for low-carbon and environmentally friendly road materials.

Performance Evaluation of Ultra-Thin Wearing Course with Different Polymer Modified Asphalt Binders

“…The pull strength of high-viscosity emulsified asphalt used in this study was thoroughly studied by the former research group. The pull strength should be higher than 0.4 MPa to ensure UTWC is closely bonded with the original cement concrete pavement [11,12,18]. The disease caused by insufficient bond strength did not occur when high-viscosity emulsified asphalt pull strength was more than 0.4 MPa.…”

“…So far, one of the widely applied preventive maintenance treatments is ultra-thin wearing course (UTWC). It is an asphalt overlay that improves pavement-surface smoothness and anti-skid performance, as well as reducing noise and repairing mild to moderate pavement diseases such as mild cracks, slight loosening, and rutting (less than 15 mm) [9][10][11]. It is economic due to its thickness being usually less than 25 mm: compared with the thickness of traditional asphalt overlay pavement (40-50 mm), UTWC saves 30-40% on material costs [12,13].…”

“…Polymers 2022, 14, 3235 2 of 21 high-viscosity and high-elasticity modified asphalt have been widely used in UTWC. These high-performance asphalt binders improve the high-temperature performance, raveling resistance, and crack resistance of UTWC [11,19,20]. Moreover, some researchers focused on the influence of gradation on UTWC performance.…”

“…However, studies that have compared the UTWC performance of SMA-10, Novachip-B, and GT-10 by the laboratory test are pretty limited. The performance of UTWC, such as water stability, reveling resistance, fatigue resistance, and anti-skid performance, is usually evaluated [11,[15][16][17][18][19][20][23][24][25]. Furthermore, pavement diseases, such as waves, deformations, and ruts occur after a frequent traffic load, if rutting resistance is insufficient.…”

Feasibility of Pellet Material Incorporating Anti-Stripping Emulsifier and Slaked Lime for Pothole Restoration

“…While the use of pellet material in asphalt technology shows promise as a sustainable and innovative approach to road construction, it is important to acknowledge certain limitations and identify the research needs for further exploration [35,36]. Firstly, additional studies are needed to assess the performance and durability of pelletized asphalt under different load conditions.…”