Abstract
This study aims to evaluate the effect of different rejuvenators and antistripping agents on the healing performance of hot mix asphalt (HMA). Two damage HMA series (e.g., moisture damage and aged damage) were subjected to either induction or microwave heating. A PG64‐22 virgin and aged binder were used and modified with several additives. Three long‐term aged binders (e.g., PAV5, PAV15, and PAV20) were conducted by pressure aging vessel (PAV) test. The moisture damage series fabricating with a new binder was further categorized into four different freeze‐thaw (FT) cycles (e.g., 0FT, 1FT, 3FT, and 5FT). Also, the aged series was fabricated with three different aged binders. A total of eight damage‐healing cycles were applied to all asphalt mixtures, examined by the three‐point bending test. The moisture resistance of modified asphalt mixture was examined by indirect tensile strength test. Overall, asphalt mixtures modified with either antistripping additives or rejuvenators not only obtained higher moisture resistance but also gained better healing performance under moisture damage. In addition, the study showed a probable correlation between moisture damage and long‐term aging in terms of healing performance, such as PAV15 and 3FT cycles and PAV20 and 5FT cycles.
Highlights
Moisture damage is one of the main factors affecting the durability of asphalt mixtures [1]. e application of freezing and thawing cycles is adopted to replicate in-service moisture damage on pavements
TSR is defined as the ratio of the tensile strength of both wetconditioned (i.e., 1, 3, and 5 FT cycles) and dry-conditioned samples (i.e., 0 FT cycles). e tensile strength ratio can be calculated by following equation: TSRik where TSRik is tensile strength ratio of mixture with type “K” additive agent at cycle “i,” Ki is the wet-conditioned tensile strength of mixture with “K” additive agent at cycle “i,” and
TSR of all asphalt mixtures decreased at every freeze-thaw cycle. e control mixture showed the lowest TSR values of 53% and 19% after one and five FTcycles, respectively. e decrease in TSR could be caused by the presence of more air void content after succeeding in FT cycles. e antistripping additive samples had better results compared to samples modified with rejuvenators. is can be explained by the fact that antistripping additive increases adhesion between binder and aggregates, giving stronger tensile strength
Summary
Moisture damage is one of the main factors affecting the durability of asphalt mixtures [1]. e application of freezing and thawing cycles is adopted to replicate in-service moisture damage on pavements. Moisture damage greatly affects internal structure and results in pavement degradation. Moisture damage can be prevented either by improving the adhesion strength of asphalt aggregate or by preventing water intrusion on asphalt concrete [4]. Is additive agent can improve internal structure of asphalt mixture, which enhances the adhesive of aggregate and binder [5]. In addition to reducing water intrusion, microcracks healing is a promising solution [6]. Electromagnetic induction, microwave, and infrared have been used to heat asphalt concrete for healing purposes. It has been proved that the healing level of asphalt concrete can be improved by induction and microwave heating. Mixture containing conductive additives is exposed to high frequency alternating magnetic fields. Based on the Joule law, the eddy current heats conductive particle
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