Performance Characterization of Asphalt Concrete Mixtures Modified with a Latex Additive

Improving the cracking susceptibility of the asphalt concrete (AC) layers in flexible pavement structures has become a major challenge, especially with the more frequent use of recycled materials, warm mix asphalt technologies, additives, and modified binders. Establishing a performance-based analysis methodology that incorporates cracking and rutting tests is paramount for balancing the mechanical performance of AC mixtures, especially their durability and stability, during the mix design process. This paper presents an experimental evaluation of AC mixtures with the overlay tester (OT), Hamburg wheel tracking ( HWT), and indirect tension (IDT) tests. A dense-graded mix with a 12.5 mm nominal maximum aggregate size was designed and produce with five asphalt binders with different performance grade including a PG 58-28, 64-22, 70-22, 70-28, and 76-22. The PG 58-28 and 64-22 asphalt binders were also modified with 3% latex. The mechanical performance of the AC mixtures was assessed with a performance diagram formulated with the crack progression rate from the OT test, rutting resistance index from the HWT test, and tensile strength from the IDT test. Modifying AC mixtures with latex may help to improve their engineering behavior. However, test methods such as the OT, HWT, and IDT tests must be incorporated into a performance-based analysis methodology to ensure satisfactory mechanical properties of modified AC mixtures.