Bärighetskontroll av obundna material med koppling till M-E beräkningar: Enkel och snabb utvärdering av obundna materialegenskaper

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The current project consists of two main parts. The first part of the project has focused on evaluating a new testing approach that can be used to estimate the stiffness properties of unbound materials, namely the resilient modulus, using the light weight deflectometer equipment which is a simple to use and time saving field and laboratory equipment (as compared to for example Repeated Load Triaxial Test). This research is directed towards finding new relations in which the outputs of the repeated (cyclic) LWD tests can be used as input data to Mechanistic-Empirical Pavement Design software. It has been demonstrated that the deformation moduli collected by LWD are strongly correlated to the corresponding resilient moduli measured by repeated load triaxial tests under similar testing conditions for the sandy soil and base material tested in this study.

The second part of the project has been devoted to correlating parameters collected using LWD and CBR to conventional parameters collected using traditional tests, namely modified Proctor tests and static plate loading test. To reach this goal, the second part of the project studied dynamic CBR tests performed to control the material stability and assess the correlation between the dynamic CBR and other characteristics of the tested materials. It has been found that the laboratory dynamic CBR values (CBRLD) can be correlated to the compaction densities and molding water contents for the sandy soil and granular unbound material using the developed regression models for a wide range of molding water contents. A good correlation between Ev2 measured from static plate loading test and Evd measured from in situ LWD tests for the compacted sandy soil and base materials has been found as well. However, further research is required to generalize the given correlations and adopt them in practice.

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