Plate Bearing Tests for Design of Flexible and Rigid Pavements

SYNOPSIS This paper presents the results of a study of pavement design based on the plate bearing list. The report supplements previous papers on pavement design, particularly the study reported in 1952 on the use of the triaxial test for design of flexible pavements. A series of tests was conducted on a test section of the Joint Highway Research Project Test Road. These tests were conducted by loading a 30 inch diameter circular plate on various depths of com­ pacted gravel to evaluate the effect of depth of base on subgrade reaction. The data obtained from the testing program indicated that the variation of subgrade reaction with depth of base and as determined by the testing program was nearly the same as that determined by the mathematical analysis proposed by Prof. D. M. Burmister of Columbia University. It was indicated that even relatively shallow depths of base course greatly improve subgrade supporting capacities. The effects of density of reinforcing layer were studied and eval­ uated. It was concluded that the density of the granular material is important in that increases in compaction result in greatly increased subgrade support. It was concluded that the plate bearing test offers a good means for evaluating pavements. However, the need for further research before this design procedure can be adopted for pavement design in Indiana was indicated. Among the factors that must be evaluated are the effect of repeated loads, and climate.