Estudo das propriedades de engenharia e condições de umidade nos subleitos de rodovias pavimentadas no Estado da Paraíba - Brasil.

Abstract

A field and Laboratory investigation in described concerning the engineering properties and subgrade conditions of paved roads located in Paraiba State in Different topographic and climatic areas and soil formations. Subgrade materials from seventeen sections of different roads were studied. Traffic volumes for service and project times were determined and evaluated using the Murillo Lopes and the English methods. Subgrade soil resistance parameters obtained in CBR tests with and without immersion were compared with CBR value determined "in situ". A study was also carried out rela ting the distribution of moisture contents in the subgrade to the suction values obtained in Laboratory. The results obtained in this research indicated that pavement design, based on CBR result with saturated specif mens, is not adequate for dry climate regions. A CBR test for equilibrium moisture content, could possibly be an indication of the bearing capacity of the soil which can be expected in service. It is suggested that the equilibrium be taken as that which corresponds to the optimum moisture content for maximum dry unit weight. The laboratory results used to obtains the suction moisture relationships, did not provide data precise enough to evaluate the equilibrium moisture, due to the fact that the wa ter table levels were very deep and did not influence the equilibrium moisture values which were probably determined by trans ference of the water in the vapor state as well as by the transference from the shoulders to the center of the road.