Effects of Reheating Procedure and Oven Type on Performance Testing Results of Asphalt Mixtures

Abstract

Reheating and oven-aging procedures of plant-produced asphalt mixtures in laboratories are important topics to consider as performance testing of mixtures becomes more popular among agencies. Differences between laboratory equipment and procedure could significantly affect performance properties. The objective of this study is to investigate the influence of sample size, oven type, and variation in reheating/aging temperatures on the results of two performance tests on plant-produced mixtures. A selected mixture was tested for volumetric properties and performance using Hamburg wheel-tracking (HWT) and semi-circular bending (SCB-IFIT) tests. Results show that reheating mixtures uncovered and in smaller containers could significantly reduce the time to achieve aging temperature, and could make the process more efficient and consistent. In addition, aging using three different oven types showed that temperature within ovens can vary significantly depending on the location of the sample inside the oven, which affects the time required to reach the target temperature, and thus may also influence the aging of the sample. The mixture volumetric properties show that the effect of various heating conditions is marginal. Using the developed reheating/aging procedure of this study, the results of the HWT and SCB-IFIT tests showed no substantial effect of oven type on rutting and cracking resistance. The overall results indicate that there is a need to standardize the conditions of reheating, sample geometry, and to verify uniformity of temperature in ovens. Such standardization can further reduce variability and thus should be part of the AASHTO/ASTM standard procedures for quality control, or of laboratory equipment calibration procedures.

Ageing and Cooling of Hot-Mix-Asphalt during Hauling and Paving—A Laboratory and Site Study

“…If the HMA stays at a high temperature for an extended time, this can be reflected in a more severe short-term ageing [17,18]. The phenomenon is even more magnified if the HMA is left cooling and later reheated [19]. Kidd et al [20] observed that the reheating of loose asphalt mixture results in changes to mix properties, particularly in the linear viscoelastic field (resilient and flexural modulus).…”

More Practical Wheel Tracking Test for Rutting Resistance of Asphalt Mixtures

“…The plant produced samples from the South source were delivered as asphalt blocks in boxes straight from the plant in 15,000 g quantities. The reheating and preparation of the asphalt blocks followed the reheating procedure outlined in Lemke et al ( 4 ) and conditioned the samples according to AASHTO R30 protocol ( 5 ). The air voids from the South source were checked after allowing the samples to cool to room temperature as per AASHTO T166 ( 6 ).…”