Engineering Commons^™

An Analytical Investigation Of Aashto Load Equivalencies, Herbert F. Southgate

Kentucky Transportation Center Research Report

An objective of this study was to develop procedures and/or refined relationships between Kentucky ESALs and AASHTO ESALs. Kentucky load equivalency relationships are the result of mechanistic analyses based on elastic theory. AASHTO load equivalency relationships were developed from recorded empirical data collected at the AASHO Road Test. Comparison of Kentucky and AASHTO ESALs necessarily in depth analyses of AASHTO load equivalency equations C-19, D-19, and their developmental equations given in the 1972 AASHTO Interm Guide. These equations evolved from the basic format used in analyzing AASHO Road Test data.

In this investigation, the repetitions reported in Appendix A of …

Evaluation Of Procedures For Testing Aggregates, David Q. Hunsucker

Kentucky Transportation Center Research Report

This report summarizes findings of a research study conducted to evaluate aggregate testing procedures as related to aggregate soundness and durability. The objectives of the study were to determine a suitable replacement or modification of Kentucky's existing Sodium Sulfate Soundness Test for aggregates which would more accurately reflect in-service performance of concrete pavements and bridges, to correlate freezing and thawing durability data and other test data with sodium sulfate soundness data, and to develop a rational implementation criterion for use of new or modified testing procedures.

There were no observable correlations between the various test methods evaluated and the Sodium …

Pavement Designs Based On Work, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

Thickness design curves presented in the report provide a systematic methodology for the selection of equivalent pavement designs for a broad range of layered systems. This is a unified system since the failure criteria are founded on the same concept of work strain and work. The analyses of stress-strain fields in the layered systems are based on elastic layered theory. This theory is represented by the Chevron N-layered computer program.

The report also summarizes the historical development and evolution of pavement design in Kentucky.

Variations Of Fatigue Due To Unevenly Loaded Axles Within Tridem Groups, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

The effect of unevenly distributed loads on the axles within a tridem has been shown to be very significant. Equations are presented that enable the equivalent load effect for equal load distribution to be adjusted for uneven loading. Considering the relative increase and the relatively small volume of trucks currently using tridems, the equation for all tridems without regard to locations on the vehicle is recommended at this time. Consideration should be given to using equations for individual load patterns as the volume of trucks using tridems increases and more weight data become available.

Rutting Models For Asphaltic Concrete And Dense-Graded Aggregate From Repeated-Load Tests, David L. Allen, Robert C. Deen

Kentucky Transportation Center Research Report

The development of models to predict rutting in the asphaltic concrete and dense-graded aggregate layers of flexible pavements is reported. The models were developed from data obtained from repeated-load triaxial tests. Details of equipment and methodology are reported.

An asphaltic concrete base mixture was tested at temperatures of 45 F, 77 F, and 100 F. Longitudinal stress levels of 20 psi, 50 psi, and 80 psi were used. The tests were performed unconfined. Most of the specimens were tested to 10,000 cycles of loading. Three sequences of loading were used.

It is noted that temperature and stress level are extremely …