Cracking investigation on fog seal technology with waterborne acrylate and polyurethane as a clean modification approach

Abstract Under the combined effects of ultraviolet, temperature and water, the asphalt pavement would deteriorate gradually. Fog seal technology was an effective strategy of energy conservation, environmental protection and cost reduction for preventive maintenance of asphalt pavement. However, the existing conventional fog seal materials based on asphalt emulsion still could not satisfy sufficient durability and were suffered various surface damages, especially the fatigue and thermal cracking problems. This research investigated the feasibility of applying waterborne acrylate and waterborne polyurethane to further improve the cracking resistance for fog seal technology, as a cleaner modification approach. The compatibility of waterborne acrylate and polyurethane in fog seal materials was observed and Gel permeation chromatography test was carried out to release the constituent mitigation during the chemical interaction between asphalt emulsion and waterborne additive. Additionally, fatigue factor test by dynamic shear rheometer was measured and linear amplitude sweep test was also applied to further evaluate the fatigue cracking resistance. The analyses of thermal cracking resistance at low temperatures were conducted through bending beam rheometer test and shear relaxation test. Finally, the relationship between chemical constituent and cracking resistance was conducted to release the effect of waterborne additive on fog seal material through statistical analysis. It presented that asphalt-additives interaction with polymer network formation improved thermal cracking resistance of fog seal materials, with large molecular size from 3.3% to 7.6%. This research revealed that the waterborne cationic acrylate in styrene-butadiene styrene modified emulsified asphalt presented significant application potential for fog seal technology with synergy effect.