Waste residue generated during the production of toluene diisocyanate was used as a modifier in making improved waterproofing bitumen. The waste particles were surface-modified with stearic acid. Various bitumen blends based on untreated particles, surface-treated particles, and a combination of an SBS elastomer and waste particles were prepared. The optimized blends were subjected to evaluate their response against temperature and frequency sweeps. It was observed that improvement of the softening point and reduction in penetration could be correlated with the blend morphology in terms of the compatibility between the waste particles and the bitumen. The increased glass transition temperature and satisfactory phase miscibility in the modified bitumen observed in MDSC and DMA traces supported these findings. The coefficient of linear thermal expansion of the modified bitumen was found to be 1.21 ϫ 10 Ϫ4 / o C. The rheological studies revealed that time-dependent properties of the modified bitumen were better in terms of its stiffness and elasticity than that of neat bitumen. The applicability of the WilliamsLandel-Ferry (WLF) equation confirms the superior temperature-dependent response of the modified systems over the control. It was noticed that stearate-treated waste-modified bitumen gives the best results in terms of a high complex modulus and a low phase angle. The newly formulated bituminous blend based on stearate-treated waste meets the requirement of existing standard specifications for waterproofing felt.

Micronized poly(vinyl chloride) (PVC) pipe waste has been employed as a soft filler in making bituminous products. The binder used in this study consists of styrene-butadiene-styrene-modified bitumen, isocyanate production waste, and an antioxidant. The time-dependent properties of these binders were assessed by constructing a master curve using frequency multiplexing. A plateau at intermediate and low frequencies in the storage modulus curves of modified bitumen implies the existence of molecular association among the constituents compared to neat bitumen. The enhanced adhesion between the PVC particles activated by H 2 O 2 and the bitumen was verified in terms of bitumen anchorage onto particles after washing in hot toluene. Confirmation of these effects can also be seen by increased stiffness of the bituminous mix with the activated particles over that with nonactivated particles. Consequently, a suitable mastic composition consisting of these activated coarse and micronized particles, limestone dust, and polymeric bituminous binder has been achieved. The results indicate that the optimized mix can be used as waterproof roof mastic as an alternative to conventional bituminous mastic.

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