School of Engineering, Makerere University, P.O. Box 7062, Kampala, Uganda
Bagampadde, U., School of Engineering, Makerere University, P.O. Box 7062, Kampala, Uganda; Kaddu, D., School of Engineering, Makerere University, P.O. Box 7062, Kampala, Uganda; Kiggundu, B.M., School of Engineering, Makerere University, P.O. Box 7062, Kampala, Uganda
This study evaluated rheological properties of low density polyethylene (LDPE) modified asphalts using conventional methods (penetration, softening point and rotational viscosity) and dynamic mechanical analysis (DMA). In addition, Marshall Properties and moisture damage of mixtures from these asphalts and four aggregates were studied using ASTM D1559 and ASTMD4867. LDPE modification improved asphalt temperature susceptibility. Practical LDPE dosages obtained were 2.5% and 3.0% (w/w) for 60/70 and 80/100 asphalts, respectively. LDPE addition slowed down approach of asphalt to a pure viscous liquid while increasing complex modulus at high temperature. The modified asphalts exhibited pseudo-plasticity and LDPE reduced shear susceptibilities of 60/70 and 80/100 asphalts by 16% and 34%, respectively. Modified mixtures exhibited stability increase to a maximum followed by a decrease possibly because of stretching of asphalt by LDPE. The total voids in mix remained within 3-5% for LDPE dosages between 0 and 3%. Limestone mixtures resisted moisture damage, while pumice behavior was asphalt specific. Neat granite and quartzite mixtures did not resist moisture damage though LDPE made them resistant. © Chinese Society of Pavement Engineering.
