Resilient Characteristics of Modified Subgrade Soil

Abstract

Abstract

The problems with poor subgrade soil which is considered as the foundation for the flexible pavement regarding the deformation under load repetitions is a major concern for road engineers. The Poor subgrade soil may be improved by stabilization or implication of soil reinforcements. In this work, the pneumatic repeated loading testing techniques has been implemented for assessing the influence of both techniques on the resilient characteristics of subgrade soil. Cutback asphalt was implemented for soil stabilization, while soil reinforcements such as geogrid, geotextile and geosynthetics are considered for subgrade improvement. Specimens of 152 mm diameter and 114 mm thickness have been prepared in the laboratory using CBR molds and static compaction to achieve a target density. Specimens were subjected to pneumatic repeated loading of 1.0 second and 0.9 second of rest period. The accumulated deformation was detected through LVDT. Data have been analyzed and compared. It was concluded that the deformation at failure under pneumatic repeated load decreases by (12, 40, and 62) % when geogrids, and geosynthetic, and geotextile reinforcements have been introduced. The reduction of deformation for asphalt stabilized soil was in the range of (85-89) % under pneumatic repeated loading for various asphalt content. The resilient modulus increases by a range of (160-336) % for asphalt stabilized soil at various asphalt percentages, while the variation in resilient modulus was not significant when soil reinforcement was implemented as compared to pure soil condition.

Keywords:Resilient modulus,Subgrade,reinforcement, repeated load, deformation, Cutback asphalt

Cite this Article
Saad Issa Sarsam, Ahmad Zuhair AL
Sandok. Resilient Characteristics of
Modified Subgrade Soil. Trends in
Transport Engineering and Applications.
2017; 4(3): 28–37p.