Optimum Properties of Geocell Reinforcement for Sustainable Low-Volume Paved Roads
Geocells are three-dimensional honeycomb-like geosynthetic structures filled with available geomaterials that vastly improve shear strength of those materials. Geocells provide a possible viable solution for thinly paved roads that use marginal infill geo
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Abstract Geocells are three-dimensional honeycomb-like geosynthetic structures filled with available geomaterials that vastly improve shear strength of those materials. Geocells provide a possible viable solution for thinly paved roads that use marginal infill geomaterials. The objective of this study was to find an optimum geocell design that utilizes various infill materials and a thin hot-mix asphalt (HMA) overlay. To achieve this study objective, four pavement test sections were constructed at the accelerated pavement testing (APT) facility of the Civil Infrastructure System Laboratory at Kansas State University. Three out of the four lanes contained geocell-reinforced bases with three individual infill geomaterials: crushed limestone, quarry by-products, and recycled asphalt pavement. The fourth test lane, the control section, consisted of a crushed stone base. All sections were heavily instrumented. Repeated loads (80 kN, single axle) were applied using an APT load assembly. Sections with an HMA layer of 50 mm reached the failure criteria of a 12.5 mm rut depth after 10,000 passes due to excessive stress in the subgrade. Redesigned sections with HMA overlay of 100 mm carried more than 1,000,000 passes. Numerical simulation of the APT tests was done using the finite element model. The optimum infill geomaterial property, geocell height, and overlay thickness were obtained from this simulation. Keywords Gerocell
RAP Low-volume roads Numerical simulation APT
B. Bortz (&) M. Hossain Department of Civil Engineering, Kansas State University, Manhattan, KS 66506, USA e-mail: [email protected] M. Hossain e-mail: [email protected] © Springer International Publishing Switzerland 2016 J.P. Aguiar-Moya et al. (eds.), The Roles of Accelerated Pavement Testing in Pavement Sustainability, DOI 10.1007/978-3-319-42797-3_13
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B. Bortz and M. Hossain
1 Introduction Geocells are three-dimensional (3-D) honeycomb-like geosynthetic structures filled with an infill of granular materials, as shown in Fig. 1. This type of geosynthetic has recently garnered increased interest as reinforcement for base courses of pavement structures for low-volume roads. Geocells are made of strips of polymer sheet or geotextile connected at staggered points so that a large honeycombed mat is formed when the strips are pulled apart. Geocells mainly provide physical containment of an infill geomaterial. Geocells can be shipped to the job site in a collapsed configuration, thereby increasing shipping efficiency. At the job site, geocells are placed directly on the surface of the subsoil and propped open in an accordion fashion with an external stretcher assembly. They are then filled with geomaterials and compacted (Koerner 1994). Because of their inherent (3-D) structure, geocells currently experience more widespread use for confinement applications than any other planar geosynthetic reinforcement (Yuu et al. 2008). However, research studies on geocells have primarily demonstrated use of geocells for increasing bearing capacity and reducing settle
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