Improving the mechanical performance of poroelastic road surface with low polyurethane content through surface activation

• Published in: Construction & building materials 2022-03, Vol.323, p.126543, Article 126543
• Main Authors: Liao, Gongyun, Fang, Xin, Hu, Jianying, Wang, Hao, Xu, Tao, Chen, Jun
• Format: Article
• Language: English
• Subjects: Aggregate; Cantabro abrasion loss; Crumb rubber; IDT strength; Mechanical performance; Molecular dynamics; PERS-LPC mixture; Surface activation
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2022.126543

[Display omitted] •UV irradiation and KMnO4 soaking are used to activate the rubber surface.•Cement and hydrated lime are added to activate the surface of the aggregate.•The effectiveness of surface activations is simulated by Molecular dynamics (MD).•The effectiveness of surface activations is verified by indoor experiments.•Optimal surface activation methods for the rubber and the aggregate are recommended. The poroelastic road surface (PERS) mixture with low polyurethane content (PERS-LPC) can reduce the construction cost of PERS pavement, which exhibits promising noise reduction capacity, whereas its mechanical performance needs to be further enhanced for real practice. This study aims to investigate the effectiveness of surface activations of crumb rubber and aggregate to improve the mechanical performance of PERS-LPC. Molecular dynamics (MD) simulations and indoor experiments have been conducted, including the indirect tension (IDT) test implemented on the dry-cured and freeze–thaw PERS-LPC specimens and Cantabro test performed on water-bathed specimens. The results showed that, the oxygen-containing groups, introduced by UV irradiation and KMnO4 soaking, enhanced surface polarity of crumb rubber and rubber-polyurethane bonding strength. The surface activity of basalt aggregate was increased by the inclusion of Portland cement but not by hydrated lime. The IDT strength of the dry-cured PERS-LPC mixture was improved by 10.3–17.5% with activated rubbers and by 35.6% with activated aggregates. The tension strength ratio (TSR) of the freeze–thaw mixture was increased only by 2% with activated rubber but up to 20.8% by the inclusion of 0.5 wt% cement. The Cantabro abrasion loss (CAL) of PERS-LPC specimens was reduced significantly from 20.1% to 11.6% with the soaked rubber and dropped dramatically to 7.9% after inclusion of 0.5 wt% cement. It was recommended to activate crumb rubber with UV irradiation for 24 h and mineral aggregate with 0.5 wt% cement in PERS-LPC mixture in terms of performance enhancement and operation convenience. The findings of this research were expected to support the mix design of an inexpensive and durable PERS-LPC mixture for noise reduction.