Evaluation of strain modulus and deformation characteristics of geosynthetic-reinforced soil – aggregate system under repetitive loading

Abstract

Geosynthetics are found to be advantageous for the improved performance of the pavements in terms of reduced permanent deformation, increased load carrying capacity and increased design life. This paper presents the results of plate load tests carried out on the unreinforced and geosynthetic-reinforced soil – aggregates systems. The soil used in this study is high compressible clay (CH) and the aggregate mix corresponds to grading II sub-base course material as per IRC guidelines. For the reinforced soil – aggregate systems, the geocell was placed at the interface of subgrade and sub-base course layers and the geogrid was placed within the sub-base course. The plate load tests were carried out as per DIN guidelines and the strain modulus of unreinforced (control) and geosynthetic-reinforced composite systems are reported. The geogrid and geocell reinforcement is found to increase the strain modulus of the soil – aggregate system by 1.2 and 1.5 times respectively compared to the control section. Based on the strain modulus, the improved CBR values are also presented in the paper. In addition, the provision of geogrid/geocell within the pavement section reduced the residual pressure at the top of subgrade by 50 to 65% resulting in improved rutting performance of the pavement. The geogrid/geocell inclusion resulted in reduced net vertical pressure by 42% (inclusive of residual pressure) at the top of subgrade compared with the unreinforced section.