Experimental Study of Strength Development in Black Cotton Soil and Granular Material Reinforced with Geogrid and Non-Woven Geotextile

Abstract

Reinforcement of flexible pavements using geosynthetics is gaining widespread application. However, there is inadequate understanding of strength development for non-woven geotextile and geogrid as reinforcement in Black Cotton Soil (BCS) and granular material in relation to cement stabilization method. Therefore, this paper presents experimental study to investigate strength development for BCS and granular material reinforced with geogrid and non-woven geotextile using California Bearing Ratio approach. The categories of samples tested were; neat, reinforced and cement stabilized. All samples were tested after 4 days' soak. Placement of reinforcement material in BCS was done at 0.3H and 0.6H for single layer reinforcement while for double layer reinforcement, it was done at both 0.3H and 0.6H. In granular soil, single layer reinforcement condition only was considered at 0.2H, 0.4H and 0.6H. Cement stabilization for both BCS and granular soil was done by the following percentages of cement increment; 1%, 2%, 3% and 4%. From the study, the strength improvement considering single layer reinforcement by geogrid and non-woven geotextile in BCS was 37.5% and 45% respectively. In granular material, CBR strength increased by 21% and 14% due to geogrid and non-woven geotextile respectively. Percentage increase in CBR of reinforced BCS corresponded to that of over >1% cement stabilization. To further enhance decision making between these strength development alternatives, it is recommended to advance it to cost analysis.