THE STUDY OF RHEOLOGICAL PROPERTIES OF BITUMEN BLENDS MODIFIED WITH DISSOLVED PLASTIC WATER SACHET
Rutting, which is permanent deformation or consolidation of asphalt pavement, is one of the flexible pavement failures. Research has shown that one of the ways of resisting this failure is by modifying the rheological properties of bitumen. This modification can be achieved by the addition of dissolved plastic water sachet (DPWS), a well-known waste in Nigeria, to bitumen. This study was conducted to investigate the effect of DPWS on the rheological properties of bitumen and at the same time reduce the environmental hazard associated with PWS disposal with consequential pavement material improvement. Bituminous blends containing DPWS at various percentages 0, 1, 3, 5, 7, 9, 11, 13, 15 and 17% by weight of conventional bitumen were used for the study. Tests on rheological properties such as dynamic viscosity, phase angle, peak shear stress and peak shear strain were carried out on unmodified and DPWS modified hot and warm bitumen blends to determine the corresponding complex shear modulus and complex shear modulus elastic portion. Results obtained from the tests were compared between control sample (0% DPWS) and DPWS modified bitumen samples. The test results showed that the dynamic viscosity increased upon addition of the DPWS at 135°C and at 165°C, it initially increased upon addition of DPWS up to 7% before it became constant till 17% DPWS addition; and the phase angle decreased upon addition of DPWS at both 135°C and 165°C for hot mix bituminous samples. Likewise, for the warm bituminous samples, the absolute viscosity increased and phase angle decreased upon addition of DPWS at both 135°C and 165°C. The best complex shear modulus elastic portion results occurred upon 9% and 17% DPWS addition for hot mix bituminous samples and upon 5% and 17% DPWS addition for warm mix bituminous samples when subjected to temperatures of 135°C and 165°C respectively. These percentages are the best to resist rutting on our traffic roads from this study.