Abstract
A series of repeated load triaxial tests were conducted in this study to investigate the influences of compaction density and postcompaction moisture variation on the dynamic elastic modulus (Ed) and plastic permanent strain (PPS) of compacted lateritic soil. Specimens were compacted at optimum moisture content (OMC) and three degrees of compaction (90%, 93%, and 96%). Then the specimens were dried or wetted to different moisture contents (OMC,OMC±3%,OMC±6%, andOMC+9%) prior to testing forEdand PPS. Results show that moisture content has greater influence on theEdand PSS than compaction degree, and the increase in moisture content leads to a decrease ofEdand an increase of PPS. Furthermore, an empirical relationship betweenEdand applied cyclic stress (σd) is developed that incorporates density and moisture variations. Three different evolution types of PPS with number of load cycles, plastic stable, plastic creep, and incremental collapse, are identified as the increase of moisture content. In addition, the critical dynamic stress (σdc) separating stable and unstable deformation is determined based on the shakedown concept. The envelope curves ofσdc-moisture of lateritic soil with different degrees of compaction are also determined to provide reference for the pavement design.
Highlights
In the field construction, subgrade soils are generally compacted at or near optimum moisture content (OMC) and maximum dry density (MDD), and as such the compacted subgrade is usually present in an unsaturated condition
Dynamic deformation properties including resilient stiffness and accumulated permanent deformation are closely related to the service performance of operated subgrade, under high-speed and heavy-axle traffic loading, limited research work has been performed on dynamic elastic modulus (Ed) and plastic permanent strain (PPS) of lateritic soil
The primary objective of this study is to address the variations of Ed, PPS, and critical dynamic stress with postcompaction moisture contents and compaction density for compacted lateritic soil
Summary
Subgrade soils are generally compacted at or near optimum moisture content (OMC) and maximum dry density (MDD), and as such the compacted subgrade is usually present in an unsaturated condition. Several recent studies have shown that variations in moisture content significantly degrade the engineering properties of compacted subgrade [6,7,8,9] and contribute to the deterioration and premature failure of pavements. Lateritic soils possess special properties with high plasticity and high water sensitivity [10], which can lead to significant moisture variation of compacted subgrade with the seasonal environmental factors. Considerable studies have been carried out on the effect of moisture variation on the shear strength and static modulus of lateritic soil [11,12,13,14,15]. It was observed that an increase in moisture content typically decreased the matric suction and decreased the shear strength and static modulus. Fall et al [16] investigated the evolution of permanent and reversible deformation of the three laterites under various cyclic stress
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
