Laboratory Study of Manganese Mining Overburden Mixed with Lime as a Paving Subbase Layer
Authors: Giovanna de Freitas Rosa1,2, Rosângela dos Santos Motta1, and Maria Eugênia Gimenez Boscov1
Conference: 14th ISAP International Conference on Asphalt Pavement
Date: June 2–7, 2024
1 Knight Piésold, Canada
2 University of São Paulo, Brazil
ABSTRACT
This paper presents the results of a laboratory investigation comprising geotechnical characterization, CBR, and resilient modulus tests carried out on a manganese overburden, in the natural state and mixed with 3% and 4% lime, to evaluate the suitability of the materials for road construction. The test results were used to calculate the allowable stresses for a typical Brazilian flexible asphaltic pavement for low volume roads. Allowable stresses considering a subbase built with lime-amended manganese overburden were compared to the stresses calculated for a lateritic clayey-sand subbase to evaluate the efficacy of the manganese overburden and its mixture with lime. The allowable stresses were converted in N (number of equivalent single axle loads - ESAL). The results of the investigation indicated that the manganese sterile with 3% lime addition and 7 days of curing time achieved slightly higher N values than the typical lateritic sub-base road for the same cross-section: N increased from 1013 to 1014 using the alternative material. This is a promising reuse alternative to introduce manganese in the circular economy and to preserve natural soils from exploitation.
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