VAA Virginia Asphalt Fall/Winter 2021

30 FALL/WINTER 2021 A Little Light Reading—Recent Asphalt and Pavement Related VTRC Publications A number of asphalt-relevant projects have been completed and final reports released during the 2021 calendar year. A quick review of recently available titles is included here, along with a QR code to read the full text of the VTRC reports. VTRC 21-R15, Balanced Mix Design for Surface Mixtures: Phase I: Initial Roadmap Development and Specification Verification. The report presents a proposed roadmap to provide guidance on the spe- cific needs and activities necessary for VDOT to adopt the BMD concept. It also documents an exercise designed to validate and/or refine the selected initial performance tests and associated test threshold criteria using 13 Vir- ginia mixtures. Report authors—Stacey Diefenderfer, Ilker Boz and Jhony Habbouche. VTRC 21-R16, Laboratory and Field Performance Evaluation of Pavement Sections with High Polymer- Modified Asphalt Overlays. This research addressed the viability of using high polymer-modified (HP) asphalt concrete (AC) mixtures in Virginia as a reflective crack mitigation technique or when deemed appropriate as a tool for increased crack resistance on higher volume facilities. It includes a state of the practice and lessons-learned review for HP AC mixtures in theU.S.and Canada, along with a more in-depth survey of performance for Virginia’s installed applications. Report authors—Jhony Habbouche, Ilker Boz and Brian Diefenderfer. VTRC 21-R21, Balanced Mix Design for Surface Asphalt Mixtures: 2019 Field Trials. This report chronicles the design, production and laboratory performance results for a series of asphalt mix field trials from the 2019 construction season. These trials represented some of the earliest work with mixes that were designed to meet the performance tests for balancedmix design. The materials in these trials included a range of RAP content and rejuvenating additives. Report authors—Stacey Diefenderfer, Ilker Boz and Jhony Habbouche. VTRC 21-R22, Structural Study of Cold Central Plant Recycling Sections at the National Center for Asphalt Technology (NCAT) Test Track: Phase III. The performance of two Virginia-sponsored test sections built using pave- ment recycling techniques on the NCAT Test Track is discussed. The two sections were subjected to approximately 30 million 18-kip equivalent single axle loads between 2012 and 2021. It concludes that pavement sections built using pavement recycling techniques can be expected to achieve a long service life under heavy truck traffic. Superior performance from a section that contained a stabilized foundation was particularly notable. Report authors—Brian Diefenderfer & Ilker Boz from VTRC; David Timm and Benjamin Bowers from Auburn. VTRC 22-R3, Round Robin Testing Program for the Indirect Tensile Cracking Test at Intermediate Temperature: Phase 1. This report describes a study designed to determine and develop pre- cision estimates and statements for the cracking tolerance index (CT index) of asphalt mixtures determined by performing the indirect tensile cracking test (IDT-CT) at intermediate temperature in accordance with ASTM D8225-19. It also includes precision estimates and statements for the fracture strain tolerance index (FST index), strength (St) and cracking resistance index (CRI) that were determined from the same IDT-CT data. Report authors—Jhony Habbouche, Stacey Diefenderfer and Ilker Boz. VTRC PROGRAM OVERVIEW FALL 2021