Recovery efficiency of the damaged porous asphalt mixture with emulsion-based surface treatment : material optimization and performance verification

Abstract

Porous asphalt (PA) road surfaces usually have short service lives due to quick raveling. Recent field trials in Europe have shown that spraying surface-treatment (ST) asphalt emulsion is a potential method to address this problem. However, the recovery efficiency of ST emulsion in PA mixture is currently unknown, limiting the wide application of this preventive maintenance technique in practice. Therefore, this study aims to investigate the key factors affecting the recovery efficiency of ST emulsion when it is applied to damaged PA. The Cantabro abrasion tests were first conducted on damaged PA specimens with and without ST emulsions to evaluate the recovery performances of different ST scenarios. The functional properties, including noise-absorption, permeability, and skid-resistance, under the optimized ST application scenario were then characterized for verification purposes. The testing results showed that the abrasion loss of the damaged PA mixture under ST emulsion was significantly reduced after 3 days of curing. Both the application rate and solid content of ST emulsion are critical factors affecting the raveling resistance recovery of the damaged PA mixture. However, the addition of the bio-based or petrol-based rejuvenator has a negligible impact on the performance recovery of the damaged PA mixtures after 14 days of curing, indicating the diffusion of the ST emulsion (if any) may require a long time in this scenario. Besides, the application of the ST emulsion may have a slight side-effect on the functional performance of PA in the short term, necessitating functional performance verification for the ST emulsion design.