Abstract
Waste residue generated during the manufacturing of toluene diisocyanate was used as a modifier for bituminous waterproofing. Waste particles were surface modified with stearic acid to obtain a uniform dispersion in bitumen. Various blends have been prepared from untreated and treated waste particles, styrene–butadiene–styrene and 85/25 industrial grade bitumen. The behaviour of these blends was evaluated in terms of constituents by DSC, SEM, FTIR and DMA techniques. The occurrence of rough and hard microstructure with unlocalised particles distribution in the modified bitumen is viewed due to improved visco-elastic response. In DSC, the presence of transitions in the melt dissolution region indicate that the newly formed separate phase remained non-dissolutive in maltenes. The emergence of new peaks in the IR spectra supported the formation of these moieties. As observed in DMA as well as in DSC spectra, influence of waste particles on the flattening of transitions in the bitumen implies that particles act as rheology improver. The high value of tan
δ between 80 and 90 °C of waste-modified bitumen confirms the existence of phase separation between the waste and the bitumen. Verification of this separation is further confirmed by obtaining the minimal difference in the results of penetration of top and bottom portion of hot stored samples. It is observed that the consistency of waste-modified bitumen is superior to the neat bitumen. The temperature dependency of the modified bitumen was also improved.