Factors Influencing Deformations of Geocell-Reinforced Recycled Asphalt Pavement Bases under Cyclic Loading

Abstract

A significant amount of recycled asphalt pavement (RAP) material is produced from flexible pavement rehabilitation projects. RAP can be used as a base course material for sustainable pavement construction. Performance of a pavement largely depends on the strength of its foundation, which consists of the subgrade and base course layers. Geocell was used in this study to increase the strength of RAP bases. Nine large-scale laboratory cyclic plate loading tests were conducted on unreinforced and geocell-reinforced RAP bases with three different thicknesses (150, 230, and 300 mm) over weak and moderate subgrades to investigate the influence of geocell confinement, base course thickness, base course strength, and subgrade strength on permanent and resilient deformations of RAP bases. The subgrade was prepared by mixing Kansas River sand with kaolin and compacted at weak [target California bearing ratio ðCBRÞ¼2%] and moderate (target CBR ¼ 5%) strengths. The test results showed that geocell confinement improved the performance of reinforced RAP bases by reducing permanent surface deformations and increasing resilient deformations and percentages of resilient deformation as compared with those of unreinforced bases. The RAP bases over the moderate subgrade performed better than those over the weak subgrade. Subgrade strength had a more pronounced effect than geocell confinement on the properties of RAP bases. Geocell confinement was more beneficial for the bases over the weak subgrade than those over the moderate subgrade. The relative improvement factors (RIFs) of the reinforced bases with respect to the unreinforced bases and the bases over the moderate subgrade with respect to the bases over the weak subgrade ranged from 1.1 to 11.4 and 1.2 to 17.2, respectively. The permanent deformation increased with the number of loading cycles and the RIFs increased with the permanent surface deformation of RAP base sections.

Response of pavement foundations incorporating both geocells and expanded polystyrene (EPS) geofoam

“…At such a stage, Powell et al (1984) showed that 500 axle passages is a likely maximum. Thakur et al (2016) only applied 100 cycles of 550 kPa pressure to evaluate deformation of geocell-reinforced recycled asphalt pavement bases subjected to repetitive loading. Similarly Sun et al (2015) who applied 100 cycles of pressure at various loading increments up to 700 kPa to investigate the performance of geogrid-stabilized unpaved roads under cyclic loading.…”

Performance of Reinforced Base Courses of Flexible Pavements Overlying Soft Subgrades: Insights From Large-Scale Model Experiments

“…Similarly, a threedimensional honeycomb structure called geocell offers overall confinement and higher load carrying capacity [1,[5][6][7]. However, their benefit in terms of reduced deformations and improved pavement performance over soft subgrades is observed when reinforcement is placed near the loading region [8][9][10][11]. In most cases, when soft subgrades are encountered, single reinforcement such as geogrid or geocell placement in the base layers may not be adequate to control the pavement deformations.…”

Frictional properties between geocells filled with granular material

“…As a result of these studies, it can be observed that the shear strengths increase significantly using geocell in soil samples. Moreover, many researchers have investigated the bearing capacity of footings with geocell-reinforced soil (Latha et al, 2006;Latha and Murthy, 2007;Dash et al, 2007;Sitharam et al, 2007;Wang et al, 2008;Moghaddas Tafreshi and Dawson, 2010;Yang et al, 2012;Tavakoli Mehrjardi et al, 2012;Tanyu et al, 2013;Dash and Chandra, 2013;Chen et al, 2013;Huang, 2014;Song et al, 2014;Han and Thakur, 2014;Moghaddas Tafreshi et al, 2015;Avesani Neto et al, 2015;Aboobacker et al, 2015;Biabani et al, 2016;Kumar and Saride, 2016;Sireesh et al, 2016;Hegde et al, 2016;Thakur et al, 2016;Mehrjardi et al, 2019). Last of all, through the studies performed on the bearing capacity of shallow foundations using reinforced soil with geocell, it was established that the bearing capacity of soil increases with the use of geocell.…”