Development and calibration of empirical and mechanistic-empirical pavement design procedures and models

2003 ◽  
Vol 1855 (1) ◽  
pp. 176-182 ◽  
Author(s):  
Weng On Tam ◽  
Harold Von Quintus

Traffic data are a key element for the design and analysis of pavement structures. Automatic vehicle-classification and weigh-in-motion (WIM) data are collected by most state highway agencies for various purposes that include pavement design. Equivalent single-axle loads have had widespread use for pavement design. However, procedures being developed under NCHRP require the use of axle-load spectra. The Long-Term Pavement Performance database contains a wealth of traffic data and was selected to develop traffic defaults in support of NCHRP 1-37A as well as other mechanistic-empirical design procedures. Automated vehicle-classification data were used to develop defaults that account for the distribution of truck volumes by class. Analyses also were conducted to determine direction and lane-distribution factors. WIM data were used to develop defaults to account for the axle-weight distributions and number of axles per vehicle for each truck type. The results of these analyses led to the establishment of traffic defaults for use in mechanistic-empirical design procedures.


Author(s):  
Anastasios M. Ioannides

Application of fracture mechanics concepts developed in various branches of engineering to the pavement problem can address current limitations, thereby advancing considerably existing pavement design procedures. The state of the art in fracture mechanics applications to pavement engineering is summarized, and an in-depth discussion of one of the major concerns in such applications, the specimen-size effect, is provided. It is concluded that the fictitious crack model proposed by Hillerborg appears most promising for computerized application to pavements. The similitude concepts developed by Bache will be very useful in such efforts. Both the desirability and the scarcity of suitable candidates to replace Miner’s cumulative linear fatigue hypothesis in conventional pavement design are confirmed. Fracture mechanics is shown to be a very promising engineering discipline from which innovations could be transplanted to pavement activities. Nonetheless, it is pointed out that rather slow progress characterizes fracture mechanics developments in general. Pavement engineers clearly need to remain abreast of and involved in fracture mechanics activities.


Author(s):  
Khaled A. Galal ◽  
Ghassan R. Chehab

One of the Indiana Department of Transportation's (INDOT's) strategic goals is to improve its pavement design procedures. This goal can be accomplished by fully implementing the 2002 mechanistic–empirical (M-E) pavement design guide (M-E PDG) once it is approved by AASHTO. The release of the M-E PDG software has provided a unique opportunity for INDOT engineers to evaluate, calibrate, and validate the new M-E design process. A continuously reinforced concrete pavement on I-65 was rubblized and overlaid with a 13–in.-thick hot-mix asphalt overlay in 1994. The availability of the structural design, material properties, and climatic and traffic conditions, in addition to the availability of performance data, provided a unique opportunity for comparing the predicted performance of this section using the M-E procedure with the in situ performance; calibration efforts were conducted subsequently. The 1993 design of this pavement section was compared with the 2002 M-E design, and performance was predicted with the same design inputs. In addition, design levels and inputs were varied to achieve the following: ( a) assess the functionality of the M-E PDG software and the feasibility of applying M-E design concepts for structural pavement design of Indiana roadways, ( b) determine the sensitivity of the design parameters and the input levels most critical to the M-E PDG predicted distresses and their impact on the implementation strategy that would be recommended to INDOT, and ( c) evaluate the rubblization technique that was implemented on the I-65 pavement section.


Author(s):  
Jong R. Kim ◽  
Leslie Titus-Glover ◽  
Michael I. Darter ◽  
Robert K. Kumapley

Proper consideration of traffic loading in pavement design requires knowledge of the full axle load distribution by the main axle types, including single, tandem, and tridem axles. Although the equivalent single axle load (ESAL) concept has been used since the 1960s for empirical pavement design, the new mechanistic-based pavement design procedures under development by various agencies most likely will require the use of the axle load distribution. Procedures and models for converting average daily traffic into ESALs and axle load distribution are presented, as are the relevant issues on the characterization of the full axle load distributions for single, tandem, and tridem axles for use in mechanistic-based pavement design. Weigh-in-motion data from the North Central Region of the Long-Term Pavement Performance study database were used to develop the models for predicting axle load distribution.


Author(s):  
Marshall R. Thompson

Activities associated with the development of the revised AASHTO Guide for the Design of Pavement Structures (1986 edition) prompted the AASHTO Joint Task Force on Pavements (JTFOP) recommendation to immediately initiate research with the objective of developing mechanistic pavement analysis and design procedures suitable for use in future versions of the AASHTO guide. The mechanistic-empirical (M-E) principles and concepts stated in the AASHTO guide were included in the NCHRP 1-26 (Calibrated Mechanistic Structural Analysis Procedures for Pavements) project statement. It was not the purpose of NCHRP Project 1-26 to devote significant effort to develop new technology but to assess, evaluate, and apply available M-E technology. Thus, the proposed processes and procedures were based on the best demonstrated available technology. NCHRP Project 1-26 has been completed and the comprehensive reports are available. M-E flexible pavement design is a reality. Some state highway agencies (Kentucky and Illinois) have already established M-E design procedures for new pavements. M-E flexible pavement design procedures have also been developed by industry groups (Shell, Asphalt Institute, and Mobil). The AASHTO JTFOP continues to support and promote the development of M-E procedures for pavement thickness design and is facilitating movement toward an M-E procedure. The successful and wide-scale implementation of M-E pavement design procedures will require cooperating and interacting with various agencies and groups (state highway agencies, AASHTO—particularly the AASHTO JTFOP, FHWA—particularly the Pavement Division and Office of Engineering, and many material and paving association industry groups). It is not an easy process, but it is an achievable goal.


1996 ◽  
Vol 34 (12) ◽  
pp. 3-8
Author(s):  
A. Kasahara ◽  
R. Sato ◽  
Y. Hachiya

TRANSPORTES ◽  
2020 ◽  
Vol 28 (2) ◽  
pp. 41-53
Author(s):  
Breno Barra ◽  
Leto Momm ◽  
Yader Guerrero ◽  
Yves Brosseaud ◽  
Gustavo Momm

The main aim of this paper is to present the development and validation procedures of the first brazilian french-based asphalt mix complex modulus and fatigue test apparatus, so-called FADECOM, in order to demonstrate the effective application of the results obtained in pavement design procedures. Magnetic sensitive Hall Effect non-contact captors determine amplitude displacement, while loading cells capture force amplitude by a diaphragm system. Independent cooling and heating chambers assure a precise temperature control comprising a range from -30ºC to above 100ºC with an accuracy of 0.1ºC. A frequency inverter controls the emission of pulses usually set from 1Hz to 30Hz. For validating the apparatus, a scientific cooperation agreement was dealt with French Institute of Transportation Sciences and Technologies, Development and Road Network (IFSTTAR), in which specimen samples were tested in both UFSC and IFSTTAR laboratories. The crossed-results obtained indicate an excellent performance and accuracy of FADECOM apparatus, presenting variations around just 3 microstrains in determining fatigue strains at 106 cycles (e6) and less than 10% related to the complex stiffness modulus, demonstrating huge accuracy of the FADECOM apparatus and its practical feasibility to be applied in pavement design procedures, based on the technical principles of French methodology.


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