A study on effect of geo-reinforcement in performance improvement of flexible pavement

Abstract

In this study, a numerical analysis is carried out for the evaluation of both unreinforced and reinforced flexible pavements based on the California Bearing Ratio (CBR) values of subgrade and traffic loads using the IITPAVE. The IITPAVE is a robust mechanistic-empirical method-based software developed by the Department of Civil Engineering, IIT Kharagpur and appreciated and incorporated by the Indian Road Congress in their standard (IRC-37). The behaviour of base, sub-base, and subgrade soil has been simulated using a linear elastic model. In the recent past, geosynthetics have been found to be a cost-effective alternative to improve weak subgrades in adverse locations. Therefore, in this study, the influence of introducing a geosynthetic material, namely the geogrid, in the base layer of flexible pavements is investigated. It is noticed that the inclusion of geogrid in the base layer of flexible pavement has reduced the base thickness by 87% as compared to the corresponding unreinforced section. This study was conducted on the reinforced and unreinforced pavement sections constructed on a subgrade having a moderate California bearing ratio (CBR) value of 5% and traffic value of 100 MSA. In this study, the flexible pavement has been designed for both fatigue and rutting life of 100MSA at 90% and 80% levels of reliability. The critical strain value for both fatigue and rutting life are analyzed by the IITPAVE and are found to be less than the prescribed allowable strain values as computed by IRC: 37-2012. The inclusion of geogrid in the pavement layer helps in improving the reduction of vertical compressive strain, and reduction in surface deformation by an amount of 57% and also provides an economical solution saving the natural resources used in pavement constructions. It is found that reinforced pavement costs approximately 40% cheaper than unreinforced pavement.