Freeze-Thaw Effects on Stiffness of Unbound Recycled Road Base - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Freeze-Thaw Effects on Stiffness of Unbound Recycled Road Base write by James M. Tinjum. This book was released on 2013. Freeze-Thaw Effects on Stiffness of Unbound Recycled Road Base available in PDF, EPUB and Kindle. A major concern for using recycled pavement material as an unbound base or subbase layer is the effect of changing seasons on the properties of the recycled material. Three sources of recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP), and one conventional base aggregate, were used to investigate the effect of freeze-thaw cycles on the stiffness of unbound road base/subbase layers. Effects of freeze-thaw cycling on the mechanical behavior of three gradations (coarse, medium, fine) of recycled materials were systematically evaluated to determine how climatic factors and aging affect the resilient modulus. Sealed specimens were exposed to 5, 10, and 20 sets of freeze-thaw cycles. Resilient modulus tests were conducted according to NCHRP 1-28A after the final freeze-thaw cycle. Freeze-thaw cycling caused a decrease in the stiffness (i.e., the summary resilient modulus) of RAP samples and class 5 aggregate because of the effect of the water retained in the pores. An increase in the stiffness of RCA was observed over 20 freeze-thaw cycles and is attributed to self-cementitious behavior of crushed concrete. Seismic modulus testing was used to investigate the continuous rate of change (daily) of the stiffness for RCA and class 5 aggregate. The seismic modulus test confirmed the trends observed in resilient modulus testing and served as a non-destructive method for tracking changes in stiffness over time and freeze-thaw cycling.
Predicting the Effects of Freezing and Thawing on Pavement Support
Predicting the Effects of Freezing and Thawing on Pavement Support - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Predicting the Effects of Freezing and Thawing on Pavement Support write by Craig H. Benson. This book was released on 1998. Predicting the Effects of Freezing and Thawing on Pavement Support available in PDF, EPUB and Kindle. The objective of this study was to develop a method to predict the timing of weight limits on secondary highways in Wisconsin. Two types of weight limits are of interest: overloads when the pavement is frozen and weight restrictions during thawing and post-thawing recovery period. To meet this objective, three sections of secondary highways with flexible pavements were instrumented and monitored to determine how freezing, thawing, and post-thaw recovery affect pavement stiffness. Data collected from these sites were used to develop a computer model (UWFrost) that can be used to predict seasonal changes in the support capacity of pavements.
Recycled Unbound Materials
Recycled Unbound Materials - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Recycled Unbound Materials write by Tuncer B. Edil. This book was released on 2012. Recycled Unbound Materials available in PDF, EPUB and Kindle. The objective of this project was to characterize the properties of crushed recycled concrete (RCA) and asphalt pavement (RAP) as unbound base without being stabilized, to assess how RCA and RAP behave in the field and to determine how pavements can be designed using RCA and RAP. Issues to be considered include variability in material properties, purity of material, climatic effects, how to identify and control material quality, and leaching characteristics. This project included laboratory specimen and large-scale model tests and evaluation of field data from MnROAD test sections constructed using recycled materials. To identify the characteristics of RAP and RCA typically available in different parts of the country, samples were obtained from eight states: California, Colorado, Michigan, Minnesota, New Jersey, Ohio, Texas, and Wisconsin covering a geographically diverse area. A conventional base course was used as a control material. The extensive investigation undertaken on RCA and RAP indicate that these materials are generally suitable for unbound base course applications and they show equal or superior performance characteristics compared to natural aggregates in terms of stiffness, freeze-thaw and wet-dry durability, and toughness. Their typical compositional and mechanical properties and their variability are defined in this study providing a basis for design considerations. Their relative differences from natural aggregate such as temperature sensitivity, plastic deformations, and water absorption and retention characteristics are also well established. It is noted that some RAP may be sensitive to temperature change that may lead to rutting. This aspect needs to be considered in design.
Significant Findings from Full-scale Accelerated Pavement Testing
Significant Findings from Full-scale Accelerated Pavement Testing - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Significant Findings from Full-scale Accelerated Pavement Testing write by Wynand JvdM. Steyn. This book was released on 2012. Significant Findings from Full-scale Accelerated Pavement Testing available in PDF, EPUB and Kindle. "TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 433: Significant Findings from Full-Scale Accelerated Pavement Testing documents and summarizes significant findings from the various experimental activities associated with full-scale accelerated pavement testing (f-sAPT) programs that have taken place between 2000 and 2011. The report also identifies gaps in knowledge related to f-sAPT and where future research may be needed. NCHRP Synthesis 433 is designed to expand the f-sAPT base of knowledge documented in NCHRP Syntheses 325 and 235, both with the same title of Significant Findings from Full-Scale Accelerated Pavement Testing. f-sAPT is the controlled application of a wheel loading, at or above the appropriate legal load limit, to a pavement system to determine pavement response in a compressed time period. The acceleration of damage is achieved by one or more of the following factors: increased repetitions, modified loading conditions, imposed climatic conditions, and thinner pavements with a decreased structural capacity which have shorter design lives"--
The Effects of Freeze-thaw Cycles and Deicer Salt on the Durability of Recycled Asphalt Mixtures
The Effects of Freeze-thaw Cycles and Deicer Salt on the Durability of Recycled Asphalt Mixtures - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook The Effects of Freeze-thaw Cycles and Deicer Salt on the Durability of Recycled Asphalt Mixtures write by Shahab Moeini Feizabadi. This book was released on 2019. The Effects of Freeze-thaw Cycles and Deicer Salt on the Durability of Recycled Asphalt Mixtures available in PDF, EPUB and Kindle. In places with severe seasonal variations, such as the province of New Brunswick, asphalt mixtures are subjected to cyclic freezing and thawing during the cold months. Moreover, different types of deicers are frequently used to mitigate the effects of snow, ice, and freezing rain on the pavements to increase the safety of roadways. In partnership with New Brunswick Department of Transportation and Infrastructure (NBDTI), seven different mix designs of plant-produced asphalt mixtures, including recycled and conventional hot mix asphalt, were collected from different projects across the province. These samples were subjected to different conditions simulating extreme weather in New Brunswick before conducting multiple tests including indirect tensile strength, semi- circular bending, and abrasion resistance. It was found that freeze-thaw cycles (FTCs) resulted in a high reduction in the tensile strength of the asphalt mixtures; however, there was not any significant difference between tensile strength of conventional and recycled mixtures. Saturation of the samples in deicer salt brine prior to testing did not result in a significant effect on the tensile strength. Semicircular bending (SCB) tests found that the cracking potential of the samples almost doubled after exposing them to a single freeze- thaw cycle. Finally, abrasion resistance tests showed that conventional asphalt mixtures were more susceptible to abrasion compared to the recycled mixtures.
