Using Limestone Mining Waste to Stabilize Expansive Soils in Ceará, Brazil.

This article aims at presenting the results of an experimental study using limestone waste from a mining operation in order to reduce the swelling potential of clay soil. Initially, the physical and mineralogical characterization of the materials were conducted. Next, tests were carried out to assess the percentage of heave and swelling pressure. Oedometric compression tests were performed with flooding stress of 5 kPa, 60 kPa and 120 kPa. The tests were carried out in pure soil (S), waste (limestone powder—LP) and waste/soil mixtures at mass proportions of 40%LP/60%S, 60%LP/40%S and 80%LP/20%S. The results showed that pure clay soil exhibited high swelling potential and swelling pressure. On the other hand, the limestone powder shows no expansion. Swell pressure and percent of heave decrease with the increase of the residue content in the mixture. The results obtained demonstrate that the use of 60% waste can stabilize clay soil against swelling when submitted to a minimum stress of 62 kPa, and that incorporating 40% waste stabilizes the soil when submitted to stresses above 280 kPa. [ABSTRACT FROM AUTHOR]