Inhibitory effects of developed composite anti-aging agent on microbial degradation of asphalt

•A new composite anti-microbial aging agent is developed to reduce the asphalt aging.•Anti-microbial aging agent inhibits the reproduction of microbial consortia on asphalt.•Composite anti-microbial aging agent damages protein structures of microorganisms.•Microorganism consortia are decomposed into alcohols, phenols, carboxylic acids, etc.•Compounding scheme of developed composite anti-microbial aging agent is proposed. The shady, humid, or polluted asphalt pavement is often subjected to microorganism degradation, leading to microbial aging. To reduce the microbial aging of asphalt pavement, a composite anti-microbial aging agent was developed, and its effects on physicochemical properties of asphalt after degraded by microbial consortia for different aging periods were discussed. Test results indicate that the content of macromolecules in asphalt decreases, while the content of small molecules increases as the aging time is prolonged. The composite anti-microbial aging agent inhibits the reproduction of microbial consortia on asphalt. Further, carbon (C) element mainly presents as C–H and C–C bonds in asphalt. After aged by microbial consortia, C element content in hydrocarbons decreases, but in alcohols or hydroxyl group increases, and in carbonyl group almost unchanges. The dodecyl trimethyl ammonium chloride (DTAC) and hexadecyl trimethyl ammonium bromide (CTAB) in composite anti-microbial aging agent damage the protein structures of microorganisms to become inactive. Then microorganisms are decomposed into alcohols, phenols, carboxylic acids, etc. The zinc oxide nanoparticles (nano-ZnO) retain original crystal structures in asphalt and achieve the bacteriostatic effect through penetrating into microbial cells. The compounding scheme with DTAC: CTAB: nano-ZnO = 1:1:1 by weight shows a higher anti-microbial aging effect on the reproduction of microbial consortia on asphalt. This proportion is proposed to prepare a new composite ant-microbial aging agent for shady, humid, or polluted asphalt pavement asphalt pavement at scenicarea countryside and forest region.