Mechanical properties of styrofoam-modified asphalt binders

Abstract

In this research, Styrofoam in its waste form was first collected, disintegrated, washed and then dried prior to mixing it with asphalt. A 70-80-penetration grade asphalt binder was used and mixed with the processed waste Styrofoam. Mixing percentages of Styrofoam to asphalt (S/A) were: 0.0 % (control sample), 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, and 2% by weight of asphalt binder. Two sets of Styrofoam asphalt binders were p repared. One set of the samples was subjected to only the mixing conditions without further aging (this set consists of the unaged Styrofoam asphalt samples). The other set was subjected to short-term aging using the rotating thin-film oven test. Consistency tests including penetration, ductility, and softening point were conducted on both sets of samples. The flash point test was also conducted on both unaged and aged samples. Superpave tests including the rotational viscosity (RV) and the Dynamic Shear Rheometer (DSR) were performed. Findings of the study found that the addition of Styrofoam to asphalt binders resulted in a significant change in the asphalt binder properties at 5 percent significance level. The ratio of the ductility of aged samples to the ductility of unaged samples ranged from 0.84 to 0.92. On the other hand, the ratio of the penetration of aged samples to the penetration of unaged samples ranged from 0.75 to as high as 0.97. It was also found that the RV and the complex shear modulus (G*) value increased with the increase in the S/A percentage. Styrofoam asphalt binder is expected to produce rutting resistant mixtures that can be used for asphalt pavements at high pavement service temperature s up to 64°C.