Improving Aged Asphalt Materials with Waste Engine Oil

1. to characterize the properties of RAP-recovered asphalt binder that has been blended with waste engine oil. to characterize the properties of RAP-recovered asphalt binder that has been blended with waste engine oil. Chris DeDene Kal Johnson Zhanping You RESULTS INTRODUCTION Dynamic Shear Rheometer (DSR): Figure 1. shows the results from the DSR testing conducted. The dashed horizontal line represents the minimum expected failure value of 1.00 kPa. The addition of 25% RAP increased the overall binder stiffness. With the increase in the amount of oil, there was a decrease in the G*/Sin(δ) parameter, which translates directly to the decrease in maximum temperature performance grade. In the United States, there are an estimated 250 million registered vehicles traveling on four million miles of public roads. With such a large volume of traffic, two key waste products are generated: engine oil from the traffic and asphalt pavement material from old roads. Although the use of recycled asphalt pavements (RAP) is greatly documented, the use of RAP without modification is known to produce an overall stiffer blend. With the addition of waste engine oil, this increased stiffness can be offset in order to produce a pavement with a consistent performance grade. Improving Aged Asphalt Materials with Waste Engine Oil RESEARCH OBJECTIVE Figure 1: DSR Results Characterize the properties aged asphalt binder that has been blended with waste engine oil. Rotational Viscometer: Averaged data from the viscometer experiments can be found in figure 3.When additional oil was added to the mixture, the binder became softer, as one could expect a softening agent to do. Thus, there was a progressive decrease in viscosity with increased amounts of oil. MATERIALS A PG 70-22 virgin Asphalt binder was combined with RAP-recovered binder at the ratio of 75% neat binder to 25% RAP-recovered binder. The RAP-recovered binder was extracted from a RAP stockpile in Hancock, Michigan. The used engine oil was supplied by the Michigan Tech motor pool. The oil was a Chevron Delo 400 LE SAE 15W30 Diesel type oil. The oil was blended with the RAP blend in two concentrations; 4 and 8% by weight of total mix. With the aid of a glass rod and under continuous stirring action, the binders were mixed homogenously in a standard specimen can over a hot plate at temperatures around 150 ⁰C. Figure 2: Rotational Viscometer Results Dynamic Shear Rheometer (DSR) RECOMENDATIONS For both DSR and Rotational Viscometer test results, the asphalt became softer as increasing amounts of waste engine oil was added. The percentage of oil shows a direct relationship with decreased stiffness. It is important to note this is a preliminary study. In order to completely investigate the feasibility of using waste engine oil in asphalt pavements, more research should be conducted on different percentages of RAP binder. Additionally, an extensive range of other tests will be conducted to further assess the feasibility of using engine oils in the asphalt pavements. Rotational Viscometer TESTING Two types of tests were conducted on the prepared asphalt blends. Using a Brookfield model DV-II Viscometer, the viscosities of the binders were tested to quantify the amount of softening undergone with increasing oil. The other type of test conducted was Rheometer testing using a Bolhin CVO 120 DSR. The DSR measures the Complex Modulus (G*) and phase angle (δ) of each sample. The Superpave system uses the parameter G*/Sin (δ) as an indication of the rutting or permanent deformation standard performance criterion. When this parameter is greater than 1.00 kPa for unaged asphalt at a given temperature, the binder meets that the rutting criterion for performance and is then progressively tested at higher temperatures until it fails.