Unconventional and Simplified Approach towards Unpaved Roads: Application of Geosynthetics

A field trial was carried out to investigate the performance of different unconventional geosynthetic materials in unpaved road construction over soft ground.The test site comprises of 25 m long, by 3 m wide test sections, built on a subgrade of undrained shear strength approximately 45 kPa . One isunreinforced and serves as a control section in the study, three sections includea geotextile, and one includes a geogrid. Each test section incorporated avariable thickness of sandy gravel base course material, between25 and 45 cmthick. They were loaded in sequence by a vehicle of standard axle load.Performance of the test sections was evaluated from measurements of rut depth, base course thickness, base course deformations, geosynthetic strain, and deformed profile of the geosynthetic, with increasing number of vehicle passes.The four geosynthetic materials used exhibited a broad range of stiffness and material properties ,but the general performance of the four reinforced sections was similar on the base course layers. On contrary thinner subgrades showed a significant difference between the geosynthetics Keywords: Geo-synthetic materials, geo-textile, geo-grid, unpaved road.

The Effects of Geocell Height and Lime Stabilization on Unpaved Road Settlements at Different Water Contents

In this study, lime stabilization and geocell reinforcement methods were investigated for a clayey subgrade of unpaved road at different water contents. This study is especially important in terms of determining the soil improvement method for road construction on wet lands. The effects of the geocell height (50, 100, 150, and 200 mm) and lime content (3, 6, and 12%) on the settlement of the subgrade soil at different water contents (25, 28, 30, 32, and 35%) were analyzed. Accordingly, a large scale plate loading test was designed, and it is utilized to achieve loading-settlement curves. The bearing capacity and modulus of subgrade (k) of soil were determined. It was detected that the geocell height and lime content have different effects at different water contents, and the modulus of subgrade reaction became stable beyond a constant height of the geocell. It was understood that none of these two improvements did not meet the Highways Technical Specifications. It is detected that at least these two improvement techniques are needed to be applied together to meet the specifications for the soil examined in this study.

Unpaved road detection using optimized log Gabor filter banks

The revised unpaved road detection system (RURD) is a novel method for detecting unpaved roads in an arid environment from color imagery collected by a forward-looking camera mounted on a moving platform. The objective is to develop and validate a novel system with the ability to detect an unpaved road at a look-ahead distance up to 40 meters that does not utilize an expensive sensor, i.e., LIDAR but instead a low-cost color camera sensor. The RURD system is composed of two stages, the road region estimation (RRE) and the road model formation (RMF). The RRE stage classifies the image patches selected at 20-meter distance from the camera and labels them to either road or non-road. The classification result is used as a high confidence road area in the image, which is used in the RMF stage. The RMF stage uses log Gabor filter bank to extract road pixels that connect to the high confidence road region and generates a 3rd degree polynomial curve to represent the road model in a given image. The road model allows the system to extend the detection range from 20 meters to farther look-ahead distance. The RURD system is evaluated with two-years worth of data collection that measures both spatial and temporal precisions. The system is also benchmarked against an algorithm from Rasmussen entitled "Grouping Dominant Orientations for Ill-Structured Roads Following", which shown an average increase detection accuracy over 30 [percent].