Research on Equipment and Parameters of Jet 3D-Printing Crack Repairing Technology for Asphalt Pavement

Asphalt pavements are prone to cracking during service, which adversely affects structural integrity and service life. To enhance automation and controllability in crack repair, a jet-based 3D printing system was developed and systematically evaluated. The system adopts a dual-module architecture integrating air compression, multizone asphalt heating, and motion path control, enabling precise regulation of pressure, temperature, and deposition trajectory. Crumb rubber (CR)/styrene-butadiene-styrene (SBS) composite-modified asphalt, incorporating 4% C9 petroleum resin to improve storage stability and overall performance, was selected as the repair material based on its temperature-viscosity characteristics. Through controlled laboratory experiments on planar substrates, key process parameters were optimized. The optimal printing window was identified at a printing temperature of 150°C, a pressure range of 0–5 MPa, a printing speed of 400 mm / s , a nozzle height of 4 mm, a printing width of 5 mm, and a layer height of 0.4 mm. Under these conditions, stable jetting, uniform deposition, and improved surface integrity were achieved. The results indicate that balancing volumetric filling capacity and deposition stability is critical for jet printing of high-viscosity asphalt materials. This study establishes a reproducible process parameter framework for jet-based asphalt crack repair under laboratory-scale conditions. Although field-scale validation remains necessary, the proposed system provides a technical foundation for the development of automated and intelligent pavement maintenance technologies.