Application of Jute Geotextiles for Rural Road Pavement Construction

Abstract

A total of 5.0-km rural roads have been constructed using jute geotextiles (JGT) as field trials in different geophysical locations of Bangladesh. The project sites were so selected that subgrade California bearing ratio (CBR) values of more than 3.0% were not achievable without adopting special means. On top of subgrade, first, an improved subgrade (ISG) layer of 75 mm compacted sand is placed. Right above this ISG layer, the specified JGT is laid with proper overlapping and pegging. After this, another layer of ISG is placed. The rest of construction of pavement follows usual practice of placing a sub-base layer followed by a base layer and black top. A series of monitoring and performance evaluation has been undertaken at different time intervals by obtaining field CBR values along the same road sections to evaluate the efficacy of JGT. The test results reveal that the load-carrying capacity of the road sections increases from 1.5 to 7.0 times due to use of JGT over a range of time interval. It is hypothesized that the load-carrying capacity of JGT reinforced subgrades increases through three different mechanisms: (1) membrane action of JGT until it decomposes; (2) absorption of moisture from subgrade by JGT resulting in an increased dry density of subgrade; and, (3) consolidation of subgrade due to surcharge load of ISG, sub-base and base layer along with a percentage of traffic load. It may be noted that the economic benefit and durability enhancement of the rural roads constructed using JGT are the obvious consequences.