Effect of organo-montmorillonite nanoclay on VOCs inhibition of bitumen

The volatile organic compounds (VOCs) emission from bituminous materials can lead to serious environmental and health issues during their applications. In this study, organo-montmorillonite nanoclays were used to modify the base bitumen, and their effect on inhibiting the VOCs emission of bitumen was evaluated by pyrolysis gas chromatograph interfaced with mass spectrometer (Py-GC/MS). Laboratory ageing study was designed and tested to evaluate the effects of the nanoclay on the ageing resistance of base binder. The results indicated that the nanoclay can effectively inhibit the VOCs emission of bitumen. The reason can be that the light components of bitumen were intercalated into the interlayer space of nanoclay which limited their emission. The organic surfactant on the surface of the nanoclay played an important role to determine the compatibility between the nanoclay and the bitumen, and it finally determined this inhibition effect. The ageing resistance of modified bitumen improved not only due to the block effect of nanoclay to the oxygen invasion, but also due to its inhibition to VOCs emission at high production temperatures. Therefore, the organo-montmorillonite can function as an inhibitor of VOCs emission and at the same time improve the ageing resistance.