Appraisal of Asphalt Mixtures’ Cracking Resistance Modified with Waste Aluminum Scrap Powder (WASP) at Intermediate Temperatures

Abstract

Considering that most asphalt concrete pavement distresses are fracture-related, evaluating and quantifying mix fracture properties is essential to improved pavement design. Therefore, the first step of the study, a pre-development phase, determines the optimal value for adding waste aluminum scrap powder (WASP) with a fraction size of 2.36-0.075 mm to mixes. Based on previous digital image analysis (DIA), AlDoz and AlNibaa’e aggregates were selected from seven central, northern, and southern Iraq sources. The second post-development phase studies the testing factors of a reliable and practical semi-circular bending (SCB) test for assessing asphalt concrete mixture fracture properties at intermediate service temperatures. The development and calibration of the Marshall System into the SCB-Tester, which switched from analog to digital and computerized control, accurately predicted reference and modified mix fracture characteristics at 50.8 mm/min. Three notch lengths (25, 32, and 38) mm were selected to be studied. Five percentages of WASP (0.5, 1.0, 1.5, 2.0, and 2.5) percent were added by weight to the entire mix and compared to the reference mixture. Results indicate that 1.5% WASP decreases fracture severity and stiffen AlNibaa’e and AlDoz mixes. Increased fracture strength and toughness of modified mixes relative to the reference may dramatically increase asphalt concrete fracture resistance. Even though a higher evaluation for AlNibaa’e mixes than AlDoz with an expected difference, the impact of modifying appears to be an effective influence for AlDoz mixes with determination factors (R2) of 0.9788 and 0.9889 than that of AlNibaa’e modified coarse and fine mixes, which have R2 of 0.8535 and 0.8461, respectively.

Keywords

• scb-tester
• fracture toughness
• marshall stiffness
• wasp
• roller compaction