Evaluation of Pavement Strain Gauge Repeatability

Abstract

Pavement instrumentation gauges have been in use for a long time and have typically been used to measure and evaluate the response of a pavement system. Although information related to the installation of these gauges and the methodology for data collection and analysis have been well-documented, literature on the repeatability of these measurements is limited. Since the response from these instrumentation gauges plays an important part in modeling pavement systems, it is necessary to have a high degree of confidence in their measurements. The Florida Department of Transportation conducted this parametric experiment to evaluate the repeatability of strain gauges currently used in its accelerated pavement testing facility. Strain measurements using 28 strain gauges were made at five different pavement temperatures, three levels of load, three levels of tire pressure, and three levels of speed. The loading was applied to the pavement test section with the heavy vehicle simulator, and five replicate load passes were made at each combination of variables. Statistical analysis of the measured strain data showed that the surface strain gauges were repeatable under various conditions of temperature, load, speed, and tire pressure. The results of this study also showed that strain measurements did not vary significantly with a change in the internal tire pressure. This paper presents a description of the testing program, data collection efforts, subsequent analysis, and preliminary results obtained under accelerated pavement testing.