Comparação entre os métodos de compactação de solos por impacto e por amassamento.

Abstract

The Proctor compaction by impact is the most used laboratory method in the world to determine the maximum dry density and optimum moisture content of soil. Procedures of compaction of soil layers in the field have been evolving in recent years with regard to techniques and technologies, and in turn, Proctor tests have remained unchanged. Therefore, a more modern method of compacting soil in laboratory is necessary because the Proctor tests do not accurately simulate compression methods of the modern field, which rely on a combination of kneading, vibration and impact. An alternative that simulates these mechanisms for compacting samples in the laboratory is the Superpave Gyratory Compactor (SGC). The procedure of compaction in SGC is comparable to a steamroller that instead of delivering blows of impact it compresses by exerting pressure on and kneading the mixture. This work proposes to compare the effect of Proctor compaction (by impact) and SGC Compaction (by kneading) by using three energies (Standard, Intermediate and Modified) in three soil types (sandy, silty and silty clay), to assess the effects of these compression processes in the geotechnical behavior of these soils.Tests such as compaction, California Bearing Ratio (CBR), tensile strength by diametral compression, and unconfined compression were performed. It may be noted that the values of apparent specific gravity of dry (MEASmáx) compaction tests obtained by the method Proctor were mostly slightly higher than those obtained in the CGS. As for mechanical testing, the specimens molded in CGS showed, in general, better results of compressive strength and tensile strength by diametral compression, while for the CBR, there was a trend toward better performance of the molded CPs in Proctor. Overall, this research showed that gyratory compression in SGC is a viable method of soil compaction in the laboratory; however, for SGC to be used routinely in the compaction of soils in the laboratory, some difficulties need to be overcome, such as the high cost of equipment when compared to the cost of conventional Proctor mold equipment.