Validating the Fatigue Endurance Limit for Hot Mix Asphalt
Title | Validating the Fatigue Endurance Limit for Hot Mix Asphalt PDF eBook |
Author | Brian D. Prowell |
Publisher | Transportation Research Board National Research |
Pages | 146 |
Release | 2010 |
Genre | Technology & Engineering |
ISBN |
At head of title: National Cooperative Highway Research Program.
NCHRP Report 646
Title | NCHRP Report 646 PDF eBook |
Author | |
Publisher | |
Pages | |
Release | 2010 |
Genre | Electronic book |
ISBN |
Validating the Fatigue Endurance Limit for Hot Mix Asphalt
Title | Validating the Fatigue Endurance Limit for Hot Mix Asphalt PDF eBook |
Author | |
Publisher | |
Pages | |
Release | 2010 |
Genre | |
ISBN |
Validating the Fatigue Endurance Limit for Hot Mix Asphalt
Title | Validating the Fatigue Endurance Limit for Hot Mix Asphalt PDF eBook |
Author | Brian D. Prowell |
Publisher | Transportation Research Board |
Pages | 139 |
Release | 2010 |
Genre | Technology & Engineering |
ISBN | 0309118212 |
At head of title: National Cooperative Highway Research Program.
Laboratory Validation of an Endurance Limit for Asphalt Pavements
Title | Laboratory Validation of an Endurance Limit for Asphalt Pavements PDF eBook |
Author | Matthew W. Witczak |
Publisher | |
Pages | 26 |
Release | 2013 |
Genre | Asphalt |
ISBN | 9780309283663 |
"TRB's National Cooperative Highway Research Program (NCHRP) Report 762: Laboratory Validation of an Endurance Limit for Asphalt Pavements presents models for the hot-mix asphalt fatigue endurance limit that are responsive to asphalt binder and mixture properties and healing between load cycles and are suitable for incorporation as algorithms in Pavement Mechanistic-Empirical Design and other design methods."--Publisher information.
Integrated Predictive Model for Healing and Fatigue Endurance Limit for Asphalt Concrete
Title | Integrated Predictive Model for Healing and Fatigue Endurance Limit for Asphalt Concrete PDF eBook |
Author | Mena Souliman |
Publisher | |
Pages | 235 |
Release | 2012 |
Genre | Asphalt concrete |
ISBN |
One of the main requirements of designing perpetual pavements is to determine the endurance limit of Hot Mix Asphalt (HMA). The purpose of this study was to validate the endurance limit for HMA using laboratory beam fatigue tests. A mathematical procedure was developed to determine the endurance limit of HMA due to healing that occurs during the rest periods between loading cycles. Relating healing to endurance limit makes this procedure unique compared to previous research projects that investigated these concepts separately. An extensive laboratory testing program, including 468 beam tests, was conducted according to AASHTO T321-03 test procedure. Six factors that affect the fatigue response of HMA were evaluated: binder type, binder content, air voids, test temperature, rest period and applied strain. The endurance limit was determined when no accumulated damage occurred indicating complete healing. Based on the test results, a first generation predictive model was developed to relate stiffness ratio to material properties. A second generation stiffness ratio model was also developed by replacing four factors (binder type, binder content, air voids, and temperature) with the initial stiffness of the mixture, which is a basic material property. The model also accounts for the nonlinear effects of the rest period and the applied strain on the healing and endurance limit. A third generation model was then developed by incorporation the number of loading cycles at different locations along the fatigue degradation curve for each test in order to account for the nonlinearity between stiffness ratio and loading cycles. In addition to predicting endurance limit, the model has the ability to predict the number of cycles to failure at any rest period and stiffness combination. The model was used to predict fatigue relationship curves for tests with rest period and determining the K1, K2, and K3 fatigue cracking coefficients. The three generation models predicted close endurance limit values ranging from 22 to 204 micro strains. After developing the third generation stiffness ratio model, the predicted endurance limit values were integrated in the strain-Nf fatigue relationships as a step toward incorporating the endurance limit in the MEPDG software. The results of this study can be used to design perpetual pavements that can sustain a large number of loads if traffic volumes and vehicle weights are controlled.
Semiconductor Laser Theory
Title | Semiconductor Laser Theory PDF eBook |
Author | Prasanta Kumar Basu |
Publisher | CRC Press |
Pages | 308 |
Release | 2015-07-16 |
Genre | Technology & Engineering |
ISBN | 0415643317 |
This book provides the reader with a comprehensive background of semiconductor lasers. It covers their structure, materials, operating principles supported by proper theory, and light power output, as well as conversion efficiency and how frequently the devices can be switched on and off. It also discusses the different lasers working at different wavelengths, viz, ultraviolet, visible, infrared and mid and far infrared regions of electromagnetic spectrum along with proper structure, materials and theory.