Measurement of subgrade soil permanent deformations under repeated loadings during simple in-situ test

Abstract

is well known that permanent deformation has a significant influence on the performance of pavements because it leads an increase in maintenance operations and costs and reduces ride quality. Therefore, it is important to predict the permanent deformations during the design stage. Due to the fact that up to date there is no simple test equipment and procedure that enables a direct in-situ measurement permanent deformations of subgrade soil under repeated loading, the current research has been undertaken to evaluating new testing approach to fulfil this requirement. The current study deals with developing a new multifunctional light weight deflectometer (LWD) that can be used to determine the in-situ permanent deformations of subgrade soil due to repeated loading by simple, cheap and time saving testing approach. It was concluded that the suggested repeated light weight deflectometer test could give a powerful material assessment and pavement design tool for the analysis of compacted subgrade soil used in this study. The developed LWD that can measure the permanent deformations directly could be utilized to establish the risk level of permanent deformations in subgrade soil in pavement constructions during the design and construction stages.

Keywords

• permanent deformations
• repeated light weight deflectometer
• silty sand subgrade
• water content