ANALYSIS OF FLEXIBLE PAVEMENTS REINFORCED WITH GEOGRIDS Hema Siriwardane, Raj Gondle, and Bora Kutuk West Virginia University, Morgantown, West Virginia, U.S.A. 1. INTRODUCTION Flexible pavements are frequently used to construct highways and roads in the United States, and many existing pavements have been treated with bituminous or asphalt materials [1]. Due to excessive traffic loads, many existing pavements have already reached the end of their service life. As a result, surface treatment methods and the use of new pavement reinforcement materials have been explored to improve the performance and service life of flexible pavements. Asphalt overlays have been used to improve the performance of deteriorating pavements in the past. The application of geosynthetic materials in highway repairs has become popular in recent years due to their high strength, durability, and ability to relieve stresses by reinforcing the pavements [2, 3 and 4]. In the past, various types of geosynthetics like geotextiles and geogrids have been used to improve the pavement performance, which provided some reinforcing benefits. Recent studies [2, 5] have shown that geotextiles provided less resistance against lateral movements than that provided by glass fiber grids. According to a previous study [5], reinforcing the hot mix asphalt (HMA) layer requires that the stiffness of the fabric material be greater than that of the surrounding HMA. High tensile strength and elastic stiffness have made glass fiber grids more popular in reinforcing the pavement system. There is limited published information available on glass fiber grid reinforcement inside the HMA in a pavement system [6]. Designing a flexible pavement reinforced with glass fiber grid and evaluating the effectiveness of reinforced pavement performance is a complex problem requiring considerable research and study. This paper presents the results of an investigation on the effectiveness of glass fiber grids as a reinforcement of the HMA in a flexible pavement system. ABSTRACT: This paper presents the results of an investigation on the effectiveness of glass fiber grids as a reinforcement of the asphalt layer in a flexible pavement system. The study involved both laboratory experimental work and computer analysis of pavement sections. Twenty flexible pavement sections (with and without glass fiber grids) were constructed and tested in the laboratory as a part of the experimental study. The laboratory-scale pavement sections were instrumented with pressure cells, displacement gages, and strain gages. Test sections were subjected to 1,000,000 load applications at a frequency of 1.2 Hz. Static loading tests were conducted at intervals of 100,000 load applications. In thirteen experiments, the glass fiber grids were used in the asphalt layer. A series of computer analyses was performed to analyze flexible pavement sections using the Finite Element Method (FEM). The laboratory data were compared with results from the computer analysis. The results show that the glass fiber grid used in this study improved the pavement performance. It was also observed that the inclusion of glass fiber grid in the asphalt layer provided resistance to crack propagation. Overall, the flexible pavement sections reinforced with glass fiber grids showed better performance under laboratory test conditions. Keywords: Flexible Pavements; Glass grid; Finite Element Method; Reinforcement 1