The behavior of the mechanical mixtures soil-wood tar, soil-lime-wood tar and soil-cement-wood tar, based on the Atterberg limits California Bearing Ratio (CBR), Unconfined Compression Strength (UCS) and permeability, were studied for application in forest road pavement. Three soil samples of (ETA, NV and VS) representative of Viçosa-MG occurrences were used. Wood-tar was used 0.25, 0.5, 1, 2, 4 and 6% and lime and cement mixture.The addition of wood-tar reduced the Atterberg values significantly. It was concluded that wood-tar improved the mechanical and hydraulic characteristics of the soils, for some treatments without, however, reaching however, the patterns of mechanical resistance demanded by DNER sub-base layers of flexible pavements. Regarding the mixtures soil-lime-wood tar and soil-cement-wood tar, substantial improvement was verified in the mechanical resistance parameters in relation to the soils, mainly due to the action of lime and cement. This action was found to be stronger for the wood tar in some treatments, leading to a higher mechanical resistance than that of the mixtures soil-lime and soil-cement. Wood tar caused a decrease in mixture permeability in relation to the soil up to 10 times. Wood tar was found to be an important stabilizer only for some forest road pavement conditions, involving soil type, and wood tar type and level, suggesting that studies on this area should present a regional characteristic.
Forest road; soil-wood tar mixtures; CBR; UCS; mechanic and hydraulic characteristics
