Abstract:
Bitumen modification is an important solution to reduce the scarcity of bitumen and for
improvement of overall properties and the performance of flexible pavements. In Ethiopia one of
the major pavement distresses is rutting, there is no significant effort to minimize distress by using
modified binder of improved visco-elastic property, and also the binder grading system is not
performance based tests. Due to this, the main objective of this research is to evaluate the
rheological properties of bitumen containing different percentage of human hair waste and
improve pavement performance at high temperature. Experimental research was carried out to
determine effects of human hair additive on the stiffness of bitumen. For this study, two types of
samples have been prepared. The first was identified as control samples (neat bitumen 80/100
penetration grade). The other was modified using the same bitumen penetration grade with human
hair additive in concentrations from 3%, 6 % and 9% human hair waste (HRW) by weight of
bitumen with three samples for each percentage was used. Dynamic Shear Rheometer (DSR) tests
and Performance Grade (PG) determinations at high temperatures were carried out to evaluate the
visco-elastic properties of neat and modified bitumen samples. The major DSR tests carried out
were Amplitude sweep test (AST), frequency sweep test (FST) and Multiple Stress Creep
Recovery (MSCR). The linear visco-elastic range (LVER) of all samples were determined with
the help of Amplitude sweep test (AST) test at 10°C, 21.1°C, 37.8°C, and 54.4 °C. From the
amplitude sweep test the limiting strain was 0.91% at 6 percentage of modified bitumen sample
which was used as an input for frequency sweep test (FST). The Master curves constructed from
the frequency sweep test result shows that addition of HRW improves the behavior of asphalt
binder. In this study, modified asphalt binder increases the stiffening property of asphalt binder at
high temperature and low loading frequency. The performance grade test, the result shows that
improvement of performance grade as percentages of modifier increases. The test result obtained
from Multiple Stress Creep Recovery (MSCR), the smallest total strain value was obtained, lower
non-recoverable creep compliance (Jnr). The Percent recovery for human hair waste (HRW)
modified binders at nine percentage was not suitable. Therefore up to 6% addition of HRW
significantl y improves the resistance of asphalt binder performance.