Beginning in 1968, Benkelman beam deflection tests were run on 25 bituminous roadways located throughout the state. Tests were run before overlay, just after these projects were overlayed, one year after, and two years after. The results were analyzed to determine the strengthening effect of the bituminous overlay.
In conjunction with this study, Benkelman beam tests were run at various short intervals on a number of randomly selected flexible pavements. These results were used to develop a testing schedule (number and location of test points required) in order to assess the deflection characteristics of a flexible pavement within a given degree of accuracy.
This report describes the traffic phase of the comprehensive study, Investigation Number 183, Application of AASHO Road Test Results to Design of Flexible Pavements in Minnesota. It refines and utilizes the procedures outlined in the 1970 Investigation 183 Interim Report, Use of Traffic Data for Calculating Equivalent 18,000 lb. Single Axle Loads.
Data used in this report were collected at 41 Test Sections in 1964 and at 48 Test Sections in the 1969-1971 period.
This investigation is being conducted as part of the Highway Planning and Research Program financed jointly with Federal-Aid Funds provided through the United States Department of Transportation, Federal Highway Administration together with State Funds.
The contents within this report are basically the same as described in the November 1, 1971 revision. However, since that date, some changes in the testing procedures described therein have been determined necessary in order to have resistance values comparable to previous Minnesota data.
A comparison of the two reports will show minor revisions in the initial preparation and batching procedures and two major revisions in the procedure for performing the exudation tests.
A number of flexible pavement sections were constructed using limestone aggregate as the base material. As controls for comparison, identical sections were built using gravel base material. Evaluation was based primarily on Benkelman beam deflections. The results indicate that there is not any significant difference in the granular equivalency of the two aggregate types
