Comparing the Stiffness of Cold In-Place Recycled Asphalt Pavement to Hot Mix Asphalt: Determining the Reproducibility of the Stiffness Rebound Test
Date of Graduation
Bachelor of Science in Civil Engineering
The Stiffness Raveling Mechanism Test (SRMT) was originally developed as an indirect measure of pavement stiffness to determine a pavement’s tendency to ravel, a type of damage. Regarding rehabilitation of existing roadways by Full Depth Reclamation (FDR) Cold In-Place Recycling (CIR), concern of field repeatability was expressed (Hill & Braham, 2016).
An analysis of lab-compacted samples of CIR and Hot Mix Asphalt (HMA) was performed to determine if the results could be reproduced between CIR and HMA. Additionally, the experiment observed the effects of percent air voids, temperature, and moisture conditioning on CIR and HMA. Three samples were prepared for each of 8, 12, and 17 percent air voids for both CIR and HMA. All samples then underwent six sequential tests. The first five tests performed the SRMT on samples at temperatures of 21°C, 40°C, 21°C, 60°C, and 21°C. Following this temperature cycling, the same samples were then saturated under a vacuum in a moisture conditioning process before finally being tested once more at 21°C.
CIR and HMA responded similarly to each condition. Reductions in stiffness were observed for higher percent air voids, higher temperatures, and moisture conditioning. HMA retained higher rebound heights over the course of all testing. CIR had higher standard deviations than HMA. Viewing the test in real-time as opposed to a frame-by-frame analysis did not greatly impact measurements obtained with the SRMT.
The SRMT is a promising as an inexpensive and quick method to obtain a stiffness measurement of asphalt pavement. Due to minor differences observed between CIR and HMA, it is recommended that several more CIR and HMA mixes be tested to determine the full extent to which mixes may affect standard deviation. Modifications to the design of the SRMT may be another way to improve the consistency of the measurements.
Asphalt, Pavement, Stiffness, CIR, HMA, SRMT
Turben, T. (2022). Comparing the Stiffness of Cold In-Place Recycled Asphalt Pavement to Hot Mix Asphalt: Determining the Reproducibility of the Stiffness Rebound Test. Civil Engineering Undergraduate Honors Theses Retrieved from https://scholarworks.uark.edu/cveguht/72
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