Exploration of mechanical and structural properties of bitumen modified with polyethylene glycol and ZnO-nano particles

Abstract

Bitumen is a petroleum residue that is extensively used as a pavement material. Rutting at high temperatures is one of the limitations of bitumen in warmer regions. The aim of this study is to improve the performance and increase the temperature susceptibility of neat bitumen. In this study, polyethylene glycol (PEG) and nano ZnO have been used to modify the properties of neat bitumen. Four samples were prepared by incorporating PEG and nano-ZnO with a standard laboratory mixer. Polyethylene glycol with 2%, 4%, 6%, and 8% by weight were mixed initially with neat bitumen along with nano ZnO (1.5% and 3%). To check its applicability in the road construction industry, the blends were subjected to mechanical properties tests such as ductility, flash point, fire point, softening point, and penetration test. It was investigated that decrease in ductility ranges from a maximum of 143 (neat bitumen) to a minimum of 83 (8 wt%). Softening point increased from 54°C to a maximum of 59°C (8 wt%). Flash and fire point increase first and then decrease; the optimum content was found to be 6%. The structural properties of blends were investigated using X-ray diffraction. The spectra show there is a shift of peaks in polymer-modified bitumen (PMB) as compared to neat bitumen, which leads to homogeneous mixing. The shift of peaks is because of an increase in interlayer spacing of neat bitumen and a decrease in Bragg’s angle. FT-IR analysis shows the presence of peaks in the range of 3000–2800 cm−1 which confirms the presence of additives in modified bitumen. SEM analysis was conducted to check the quality of dispersion and to investigate the microstructure. ZnO nano particles affect the mechanical properties of samples. The physical properties of polymer-modified bitumen (PMB), PEG, and nano ZnO blends enhance the stiffness of samples at high temperatures.