COSTA, C. R. V.; COSTA, Carlos Roberto Vasconcelos.
Résumé:
This dissertation presents the results of a research developed with sixteen lateritic soils of the North and Northeast aiming at i) evaluating the methodology recommended by the DNER method and other existing methods for the determination of the support index california (CBR), ii) evaluating the effects of thermal and mechanical energies in the CBRs of the soils and iii) to verify the relationship between the CBR with immersion and the CBR without immersion. The obtained results allowed to conclude that, with respect to the methodology used to determine the CBR, the recommended amount of soil (sample) to determine the molding moisture and 500g and that for the plotting of the saturation curve when compaction becomes, it is necessary to introduce the relative density for particles larger than 2mm. Regarding the methodology recommended by the DNER, in order to determine the CBR, despite the introduced modifications, it resulted in questionable CBR values due to the variations found as well as the lack of specific studies for the determination of the repeatability of the CBR test and it is therefore impossible evaluate the values obtained in this research. Regarding the evaluation of the methodology using samples cured prior to the test, the results were inconsistent, suggesting the extension of studies with a greater number of soils. Regarding the influence of the thermal and mechanical energy induction on the CBR value, the results showed that the CBR values were affected, however, it was not possible to observe a defined trend for all soils. Regarding the results of the tests for the determination of the CBR for the immersion and immersion test specimens, for the 3 levels of mechanical energies, highly significant correlations were found.
