Affiliation:
1. School of Transportation Civil Engineering, Shandong Jiaotong University, Jinan 250357, China
2. Department of Roadway Engineering, School of Transportation, Southeast University, Nanjing 211189, China
3. Huashe Design Group, Huashe (Jiangsu) New Material Technology Co., Nanjing 210000, China
Abstract
This study investigates the application of foam asphalt (FA) to enhance the compaction effectiveness of a hot in-place recycling asphalt mixture (HIR-AM) during the HIR process of old road surfaces. Initially, the process parameters for FA preparation were determined through expansion-rate and half-life tests. Subsequently, the study focused on evaluating the impact of FA on the compaction quality of HIR-AM. Performance assessments were conducted through rutting tests, low-temperature bending tests, Hamburg wheel tracking tests, dynamic modulus analyses, and various other experiments to evaluate the road performance of HIR-FAM. Finally, the research findings were validated through practical engineering applications, and the construction process for HIR-FAM was summarized. The research results reveal that the optimal foaming temperature for SBS asphalt is 170 °C, with an ideal water content of 1.7%. Under the same compaction temperature, HIR-FAM demonstrated a significant reduction in void content, ranging from 3.8% to 21.2% compared to HIR-AM. Moreover, a higher proportion of FA usage resulted in a more substantial decrease in void content. Compared to HIR-AM, HIR-FAM exhibited notable improvements, including an 11.6% increase in dynamic stability, a 13.4% enhancement in bending strength, a 13.3% increase in maximum bending strain, an 8.1% improvement in residual stability, and an 8.5% boost in freeze–thaw splitting strength. Furthermore, HIR-FAM demonstrated superior water-thermal stability and resistance to low-frequency loads. Paving a test road verified that the adoption of foam asphalt in thermal recycling led to a compaction density increase of over 0.79% compared to traditional in situ thermal recycling sections, with improved compaction uniformity.
Funder
National Key R&D Program of China
National Natural Science Foundation of China
Beijing Scholars Foundation
Natural Science Foundation of Shandong Province
Subject
Building and Construction,Civil and Structural Engineering,Architecture
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