Swelling Potential Behavior of Expansive Soils Treated with Hydrated Lime

Ingrid Reyes Martinez Belchior¹; Michele Dal Toe Casagrande¹; Jorge Zornberg²

¹ Pontifical Catholic University of Rio de Janeiro - PUC-Rio; ² The University of Texas at Austin

Baixar PDF doi:10.20906/CPS/CB-02-0039

Resumo

This paper presents the results of an experimental program developed to investigate the effect of lime treatment on the reduction of swelling potential of an expansive soil. The swelling properties were determined using the new geotechnical centrifuge developed by The University of Texas at Austin. This new technology allows the infiltration water into the soil in shorter time than the conventional free-swell testing because of the high g-level acceleration applied in the specimens. The expansive clayey soil used in this study was Eagle Ford clay that was treated with different percentages of hydrated lime by weight of soil (between 0% and 4%). The compaction density of the specimens was varied between 94% and 100% of the maximum dry density, and the compaction moisture was varied between dry of optimum, optimum and wet of optimum moisture content. The centrifuge tests were carried out at three different g-levels acceleration in order to apply different vertical stresses during the swelling tests. The test results demonstrated that the effect of compaction density on the swelling potential is more significant when the specimens are compacted with low moisture content (dry of optimum) than specimens prepared at the optimum moisture content. However, most of the cases, higher potential swelling was observed in specimens prepared with densities near to the maximum than the specimens with lower density compaction. The results also allowed to conclude that the hydrate lime percentage required to avoid completely the swelling depends on the moisture condition and the effective stress. Samples compacted with wet of optimum moisture content required only 2% of lime to prevent the swelling behavior, whereas samples compacted at dry of optimum moisture content needed 4% of lime to avoid significant expansion at the same effective stress. The strong influence of the compaction moisture on swelling showed the same trend observed in untreated soils, where high potential swelling is produced when the specimens were compacted a

Palavras-chave: Expansive soil; Swelling; Lime treatment; Centrifuge