01732660

Component

http://www.trb.org/Publications/Blurbs/179567.aspx

To satisfy the requirements of low-volume rural roads in India, at times the road network has to be aligned through places where the subgrade soil is not suitable for road construction. Construction and maintenance of roads along the unsuitable soils have been problematic due to their inherent potential for volume change in the presence of water, which affects the performance of roads. The subgrade has to be properly treated at the construction stage itself. Otherwise, the road user and maintenance costs will increase substantially due to the deteriorated pavement performance. One way to treat subgrade is to reinforce it with geotextiles. Natural geotextile, particularly coir geotextile, is being recognized as an ideal material that is capable of offering an environmentally friendly and ecologically sustainable solution. Coir geotextiles are ideally suited for low cost applications because coir is available in abundance at very low price compared to other synthetic geotextiles. This study focuses on the interface behavior of the coir geotextile between subgrade and granular subbase layer. This will be helpful in evaluating the strength properties of pavement section with and without coir geotextile and ultimately in design of an economical section for a particular geotextile. Many researchers have studied the behavior of geotextile-reinforced pavements. The behavior of two types of jute geotextiles treated with copper sulphate under various laboratory tests were studied. Rut depth reduction using jute geotextile as reinforcement at interface of subgrade and subbase or base layer was observed. Fatigue test indicated that pavement reinforced with jute can reduce surface and subgrade deformation by 40% and 65% respectively for 106 repetitions of load. The monotonic plate load test and repeated load test conducted on test section showed that the plastic surface deformation under repeated loading was greatly reduced by the inclusion of coir geotextiles within the base course irrespective of base course thickness. A study on strength of granular subbase (GSB) underlain by a subgrade layer in terms of California bearing ratio (CBR) and bearing capacity reported that as GSB thickness increases, CBR increases from 2.5% to 55% for soil to GSB and the corresponding shear strength from 0.91 kg/cm² to 1.75 kg/cm². Most of the literature was based on laboratory plate load tests. It is very difficult to obtain the same field condition in a laboratory and thus results were varying. Also compacting the subgrade to required density and optimum moisture content for pavement construction in a tank in the laboratory is questionable. Some of the above studies assumed the pavement as two-layer system, which is not the case in actual field. The objective of this study is to compare the results obtained in the field by the conduct of plate load test and Benkelman beam deflection (BBD) test for pavement sections with and without coir geotextile. Also the pavement section with coir is with reduced thickness of granular subbase. In this study, field plate load tests are used which gives more reliable results than laboratory results. Benkelman beam method is also used to find the rebound deflection in reinforced and unreinforced pavement sections. The plate load test results indicated that the inclusion of H2M6 coir geotextiles increased subgrade reaction value when compared to that without coir geotextile. BBD results indicated that the deflection values for coir reinforced sections were less than that of the Control Section.

01730920

English

0000-0002-9198-1363

pp 294-298

2019-9

Transportation Research Circular

12th International Conference on Low-Volume Roads

Digital/other

Figures; References; Tables

Benkelman beam; Deflection tests; Field tests; Geotextiles; Low volume roads; Plate bearing test; Subbase (Pavements); Subgrade (Pavements); Thickness

India

Highways; Materials; Pavements

TRIS, TRB, ATRI

Mar 2 2020 10:46AM