Superpave Models and Software - Asphalt - Pavements

Superpave Performance Prediction Models and Mix Design Software

A key component of the Superpave system is a set of performance prediction and analysis models for predicting pavement distress. The evaluation of asphalt mix design using fundamental engineering properties is a major change from past reliance on empirical mix design systems. In July 1995, the FHWA entered into a two-phase contract with the university of Maryland (UMD) to evaluate and refine the Superpave pavement performance prediction models and the Superpave software which were developed under the Strategic Highway Research Program (SHRP). Phase I of the contract provided a comprehensive evaluation of the theory, application, implementation, overall feasibility, research results, and conclusions of the original SHRP Superpave pavement performance models system. The conclusions of this evaluation were that substantial corrections and enhancement to the load associated rutting and fatigue models were considered mandatory to make these models reliable for general acceptance and use by the highway industry. The existing non-load associated thermal fracture model was found to be in reasonably good condition, but required some corrections and enhancements prior to its release to the pavement community. For all of the models, the necessary corrections and enhancements mandated new field calibration and validation.

After a review of the UMD work and consultation with the Models Expert Task Group and with the original SHRP researchers, the FHWA Superpave Technology Delivery Team (TDT) developed a plan to complete the Superpave System and to continue effective implementation. It was determined that the effort required to correct the fundamental problems identified and to produce an implementable mix analysis system was beyond the level of effort previously contemplated for the university of Maryland's Phase II work. Many of the issues raised with the SHRP Superpave models stem from the methods used to characterize the asphalt materials, and the way that these materials characterizations are used as the basis for performance prediction.

Based on these conclusions, Phase II of the UMD contract was refocused on the work necessary to accurately characterize the asphalt concrete materials in terms of permanent deformation and fracture for subsequent use in pavement prediction models development. This work is presently under way with a planned completion date of the end of 2000. Future contracts are planned to develop environmental and aging models and the pavement response models and to incorporate these models along with the materials characterization into a calibrated and validated distress prediction model as envisioned by SHRP. The Ultimate goal is to develop a fundamental pavement performance model that integrates mix design and structural design and that can be sued as the basis of performance related specifications.

The implementation of the Superpave volumetric mix design has continued despite the revised schedule for completing the Superpave System. To support this ongoing implementation, another key objective of the UMD Phase II contract is to identify a fundamental yet simple performance test to be used in conjunction with the Superpave volumetric mix design. To date, FHWA has received the draft report on the simple performance test in which possible candidate test devices were identified and a laboratory testing plan was put forth. Materials from MNRoad have been shipped to the University of Maryland and laboratory testing of potential devices is now being conducted. It is planned to also perform these tests on materials from WesTrack. Also, a number of laboratory investigations on test specimen size and geometry have been completed in support of the simple performance test and material characterization activities. Draft test protocols for the selected simple performance test are expected by May 2000.

Another product to support the Superpave volumetric mix design system from the UMD Phase II contract is a windows-based version of the Superpave mix design software (Version 2.0) that will be turned over to AASHTO and released as the official Superpave Software. Version 2.0 consists of five independent modules: volumetric mix design, field quality control, field quality acceptance, binder verification, and test data entry. Version 2.0 was developed as a 32-bit Windows 95 application and will not work with Windows 3.1 or less. The software will require a minimum system configuration of a 100-MHz Pentium processor with 16 MB or RAM and an 800x600 SVGA color monitor. The software has been beta evaluated by a group representing State highway agencies, industry, the Superpave Centers, and FHWA. The latest version of the Superpave software was delivered to FHWA in December 1998. We have since provided the contractor with final comments and the final version of this software is now being reproduced. A limited release by FHWA to the State materials engineers and FHWA offices is planned this spring with a full distribution by AASHTO shortly thereafter.

Due to funding shortfalls that resulted from the Transportation Equity Act for the 21^st Century (TEA-21), FHWA does not have the research funding necessary to complete Phase II of the University of Maryland Models contract or the subsequent contracts that were planned to complete the Superpave mix analysis system. The importance of continuing this effort has been recognized and the University of Maryland Models contract will be completed as planned as NCHRP 9-19.

Design and Analysis Materials and Construction Technology Management and Preservation Surface Characteristics Construction and Materials Quality Assurance Environmental Stewardship	Superpave Performance Prediction Models and Mix Design Software A key component of the Superpave system is a set of performance prediction and analysis models for predicting pavement distress. The evaluation of asphalt mix design using fundamental engineering properties is a major change from past reliance on empirical mix design systems. In July 1995, the FHWA entered into a two-phase contract with the university of Maryland (UMD) to evaluate and refine the Superpave pavement performance prediction models and the Superpave software which were developed under the Strategic Highway Research Program (SHRP). Phase I of the contract provided a comprehensive evaluation of the theory, application, implementation, overall feasibility, research results, and conclusions of the original SHRP Superpave pavement performance models system. The conclusions of this evaluation were that substantial corrections and enhancement to the load associated rutting and fatigue models were considered mandatory to make these models reliable for general acceptance and use by the highway industry. The existing non-load associated thermal fracture model was found to be in reasonably good condition, but required some corrections and enhancements prior to its release to the pavement community. For all of the models, the necessary corrections and enhancements mandated new field calibration and validation. After a review of the UMD work and consultation with the Models Expert Task Group and with the original SHRP researchers, the FHWA Superpave Technology Delivery Team (TDT) developed a plan to complete the Superpave System and to continue effective implementation. It was determined that the effort required to correct the fundamental problems identified and to produce an implementable mix analysis system was beyond the level of effort previously contemplated for the university of Maryland's Phase II work. Many of the issues raised with the SHRP Superpave models stem from the methods used to characterize the asphalt materials, and the way that these materials characterizations are used as the basis for performance prediction. Based on these conclusions, Phase II of the UMD contract was refocused on the work necessary to accurately characterize the asphalt concrete materials in terms of permanent deformation and fracture for subsequent use in pavement prediction models development. This work is presently under way with a planned completion date of the end of 2000. Future contracts are planned to develop environmental and aging models and the pavement response models and to incorporate these models along with the materials characterization into a calibrated and validated distress prediction model as envisioned by SHRP. The Ultimate goal is to develop a fundamental pavement performance model that integrates mix design and structural design and that can be sued as the basis of performance related specifications. The implementation of the Superpave volumetric mix design has continued despite the revised schedule for completing the Superpave System. To support this ongoing implementation, another key objective of the UMD Phase II contract is to identify a fundamental yet simple performance test to be used in conjunction with the Superpave volumetric mix design. To date, FHWA has received the draft report on the simple performance test in which possible candidate test devices were identified and a laboratory testing plan was put forth. Materials from MNRoad have been shipped to the University of Maryland and laboratory testing of potential devices is now being conducted. It is planned to also perform these tests on materials from WesTrack. Also, a number of laboratory investigations on test specimen size and geometry have been completed in support of the simple performance test and material characterization activities. Draft test protocols for the selected simple performance test are expected by May 2000. Another product to support the Superpave volumetric mix design system from the UMD Phase II contract is a windows-based version of the Superpave mix design software (Version 2.0) that will be turned over to AASHTO and released as the official Superpave Software. Version 2.0 consists of five independent modules: volumetric mix design, field quality control, field quality acceptance, binder verification, and test data entry. Version 2.0 was developed as a 32-bit Windows 95 application and will not work with Windows 3.1 or less. The software will require a minimum system configuration of a 100-MHz Pentium processor with 16 MB or RAM and an 800x600 SVGA color monitor. The software has been beta evaluated by a group representing State highway agencies, industry, the Superpave Centers, and FHWA. The latest version of the Superpave software was delivered to FHWA in December 1998. We have since provided the contractor with final comments and the final version of this software is now being reproduced. A limited release by FHWA to the State materials engineers and FHWA offices is planned this spring with a full distribution by AASHTO shortly thereafter. Due to funding shortfalls that resulted from the Transportation Equity Act for the 21^st Century (TEA-21), FHWA does not have the research funding necessary to complete Phase II of the University of Maryland Models contract or the subsequent contracts that were planned to complete the Superpave mix analysis system. The importance of continuing this effort has been recognized and the University of Maryland Models contract will be completed as planned as NCHRP 9-19.	Events International Warm Mix Asphalt Conference Marriott Nashville Airport Hotel, Nashville, TN November 11-13, 2008 View all Upcoming Pavements Events More Information Pavement Publications Contacts John D'Angelo Office of Pavement Technology 202-366-0121 E-mail John Matthew Corrigan Office of Pavement Technology 202-366-1549 E-mail Matthew
	This page last modified on 05/30/06

Superpave Performance Prediction Models and Mix Design Software

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