There is growing interest in asphalt technology in the use of polymer-modified binders. This paper describes an investigation to quantify the effect of polymer modification to a Colombian asphalt on hot-mix asphalt performance. Mixes prepared with binders with varying percentages of styrene-butadiene-styrene (SBS) were studied. An oil-based additive was necessary to lower the mixing temperature to a manageable level for polymer contentsabove 3%. Tests conducted included traditional binder and mix design tests, as well as dynamic characterization of the mixes using the Nottingham Asphalt Tester. The modified asphalts showed lower thermal susceptibility and greater consistency than the base asphalt. The increment in the modifying agent improves resistance to plastic strain that can occur at high temperatures, based on the increment in the softening point. Additionally, the asphalt elasticity is improved. Dynamic characterization of mixes produced with the modified binders showed that the binder modified with 3% SBSpresents a higher dynamic modulus, which translates into a lower rutting risk. All the mixes with modified asphalts showed higher permanent deformation resistance than mixes with unmodified binders. The results suggest that mixes with modified binders can outperform conventional mixes for specific pavement distresses. However, the modification should be conducted taking into account behavioral characteristics of the pavement, such as deformation, dynamic modulus, and fatigue, along with specific characteristics of the project. Any application of additives will have direct influenceon asphalt mix behavior and, therefore, on road performance.
Abstract