Controle da expansão dos solos com resíduos de mármore e cal.

Abstract

Expansive soils cause damages in the civil engineering works, consequently it is necessary the understanding of the mechanism of expansion and control it. Stabilization of soils is an alternative to control soil expansion. This technique is used to improve mechanics, hydraulics and deformability characteristics of soils. Hydrated lime is among the most used stabilizers in soil stabilization. However, socio environmental costs inherent production of hydrated lime encouraged research using industrial wastes as stabilizers. Marble dust is a potential stabilizer due to its chemical constitution. The efficiency of a stabilizer is associated with a density that stabilized soil is compacted. Therefore, this work aims to evaluate the influence of porosity and volumetric content of hydrated lime and marble dust on expansion and mechanical strength of an expansive soil stabilized with these additives. The expansive soil used in this work was collected in Paulista-PE and was stabilized with additions of marble dust in contents of 30%, 40% and 50% of the dry soil mass and additions of lime of 2%, 4%, 6% and 8% of dry mass. The specific weight of the specimens ranged from 14 kN/m3 to 16 kN/m3. The tests performed were unconfined compressive test, expansion in one dimension with overload of 10 kPa and triaxial compression consolidated and not drained. Results indicate that marble dust can control soil expansion, however it behaved as an inert addition. By means of the triaxial tests it was verified that marble dust promoted a gain of 13 kPa in effective cohesion of the soil. Soils stabilized with lime developed pozzolanic reactions and increase of resistance to unconfined compression strength. Lime proved be efficient in expansion control, with expansion values close to 1% for the 6% lime content. A porosity/volumetric ratio of additive adjusted by an exponent, integrating porosity and additive content factors, with a one-dimensional expansion for the soil-lime and the marble dust-soil and unconfined compression strength to soil-lime. Through statistical analysis of variance and tukey test, it is possible to observe the significance of additives content and soil density in both the expansion and the unconfined compression resistance.