In this paper, the key technologies in the construction process of hot in-place recycling were investigated in order to improve the utilization rate of waste asphalt mixture; traditional lab tests including penetration, softening point and ductility tests, atomic force microscope test of recycled asphalt under different rejuvenator content, and the test of milling on grading at different temperatures were carried out. The influence of RAP content and rejuvenation processes on road performance were studied, and the low-temperature performance of mixture was analyzed by the energy analysis method, and the evaluation index was proposed. Test results indicated that the penetration and ductility increases, the softening point decrease with the rejuvenator content increasing, and the optimum rejuvenator content is 4%. The optimum mixing and compaction temperature will decrease by 2–6 °C on average for every 10% increase of RAP content by analyzing the mixture volume index. The results showed enhance rutting resistance of the mixture but lower moisture resistance and low-temperature crack resistance by adding the RAP content. The strain energy density of 10 KJ/m³ is proposed to evaluate the low-temperature performance of the mixture, and 30% RAP produces optimal mixture. The higher rutting resistance and moisture resistance can be obtained by using the construction process of RAP+ rejuvenator co-heating, and higher low-temperature crack resistance with RAP+ rejuvenator without heating.

In highly urbanized plain river network regions, the effects of land use on water quality exhibit pronounced scale dependence, yet the characteristic response scale and associated source–sink mechanisms remain insufficiently understood. Taking the Wenruitang River Basin as a case study, this research integrates high-resolution land-use data with multi-site water quality monitoring to explore scale-dependent land use–water quality relationships. Circular buffer zones of 100 m, 300 m, and 500 m were delineated around monitoring sites, and Spearman correlation analysis and RDA were applied. The results indicate that land-use explanatory power follows a clear inverted U-shaped pattern with increasing scale, peaking at the 300 m buffer, where land-use composition explained 96.56% of the variation in water quality. This scale represents the characteristic response distance of water quality to landscape structure in plain river networks. At this scale, built-up land shows significant positive correlations with NH₄⁺–N, TP, and CODMn, acting as the dominant pollution source, whereas forest and grassland exhibit significant sink functions. However, the strong dominance of built-up land relative to limited ecological land creates a source-dominated and sink-deficient configuration, constraining water quality improvement. These findings emphasize the importance of scale-aware management and suggest that water quality control should extend beyond narrow riparian buffers to the 300 m core influence zone through impervious surface regulation and low-impact development measures.