Effect of Geogrid Reinforcement on Strength, Thickness and Cost of Low-volume Rural Roads

Pavements constructed over poor subgrade soil will lead to rapid increase in construction and maintenance costs due to increase in crust thickness and frequent failure. In a developing country, like India, costs play a very significant role. In India, more than 20% of the land area is covered with soils having low California bearing ratio (CBR) and shear strength values. These soils consist of a substantial amount of fines; i.e., a high percent of silt and clay, losing significantly in strength upon coming in contact with water. This paper presents the effect of geogrid reinforcement on the strength behaviour of poor subgrade soil. The geogrids are placed in single and double layers from the top of mold and heavy compaction and soaked CBR tests are performed. It is observed that geogrid reinforcement increases the CBR value significantly, thus causing significant reductions in pavement thickness and cost. Multiple linear regression models were developed for predicting soaked CBR.