Energias para compactação de solos destinados a estruturas de pavimentos asfálticos

Abstract

Currently, the most used pavement design method in the country was proposed by DNIT, which is based on the California bearing ratio (CBR). The method stablishes minimum values for CBR according to the pavement layer, and also stablishes standards for compactive efforts, granulometry and consistency limits of geotechnical materials in pavements. However, there are alternative compactive efforts – named Interstandard Proctor and Intermodified Proctor – which represent more options to meet the technical design specifications with lower costs. In this study, the alternative compactive efforts were tested and results were compared with standard ones. Two soil types were used for this matter, both are lateritic soils (IGNATIUS, 1991): ‘Campus Glória’ sample was classified as A-7-5 by the TRB, with 90% of fines and liquidity limit = 73%; and ‘Água Limpa’ Experimental Farm sample, which is a sandy soil with 30% of fines, liquidity limit = 31% and classified as A-2-4. When hypothetical pavement structures were designed with these soils and the alternative compactive efforts, potential cost reduction were verified. One of the options suggests cost reduction of R$ 13,575.00/km if the subgrade composed by ‘Água Limpa’ soil is compacted at Interstandard Proctor effort (CBR = 23%) instead of Standard Proctor (CBR = 12%). Another option, with the ‘Água Limpa’ soil as subbase layer, would lead to an approximate saving of R$ 336.00 per kilometer of road if Interstandard Proctor compactive effort (CBR = 23%) were used instead of Itermediate Proctor (CBR = 50%).