APPLICATION OF ABAQUS PROGRAM TO INVISTIGATE THE EFFECT OF VARIATION IN SUBGRADE LAYER PROPERTIES ON THE DAMAGE OF FLEXIBLE PAVEMENT STRUCTURE

Abstract

The major purpose of the pavement structure is to reduce stresses in the subgrades so that there is little or no deformation in the subgrade. Therefore, the more the subgrade is resistant to deformation, the thinner the pavement will be, thus reduction in the construction cost of the road. Finite Element techniques can be effectively applied to simulate different pavement problems that could not be modeled using the simpler multi-layer elastic theory. Thus, finite element Abaqus 6.14-1 program is used in this study. The laboratory tests are carried out on both the natural and stabilized soil samples that used as subgrade layer to determine the properties of subgrade that will be used as inputs for the finite element Abaqus program. The natural samples tested with three percentages of moisture contents (11.5%, 13.5%, and 15.5%). Different types of stabilizers are used in this study in form of mixture of two types of stabilizers. So, mixture of lime-kaolin (3%, 4%), mixture of silica fume-Poly Vinyl Alcohol (2%, 2%), mixture of Rice Husk Ash-Poly Vinyl Alcohol (3%, 2%), and 2% of silica fume are used as stabilizers. The pavement application by Abaqus program indicating that, the characteristics of subgrade layer have a big influence on the vertical deformation of whole pavement. The combination of (3% of Rice Husk Ash and 2% of Poly Vinyl Alcohol) as a stabilizer to the subgrade layer reduces the deformation about (9.5 %). While the addition of (3% of Lime and 4% of Kaolin) led to regard the deformation about (7.8%).