Sedimentos del ex lago de Texcoco y su comportamiento con la aplicacion de materiales calcareos y compactacion | Sediments of the ex-Lake of Texcoco, and their behavior with the application of calcareous materials and compaction
2004
Lopez-Avila, G. | Gutierrez-Castorena, M. del C. | Ortiz-Solorio, C.A. | Flores-Roman, D. | Segura-Castruita, M.A.
For a long time, specialists in soil mechanics have made great efforts to keep buildings in Mexico City from sinking, by injecting cement and mortar into the subsoil. However, it has not been explained how this process occurs at the microscopic scale. The objectives of this work were to identify the morphological changes in lacustrine sediments with application of several calcareous materials, to evaluate their physical, chemical, and mechanical properties and to determine the behavior of the fine fraction in the compaction process. Bulk samples of 3.2 kg were collected from the bed of the former Lake Texcoco, and six experiments were carried out in which Ca(OH2), (CaCO3), and CaO were applied to sediments with different moisture contents (in the field, and one and two weeks of air drying). In addition, physical, chemical, and mechanical (compressibility) analyses were performed. The morphological changes during the stabilization process were registered in thin sections. The results showed that calcareous materials did not mix with amorphous lacustrine sediments due to the strongly alkaline pH (> 10), which causes their precipitation, and the high moisture contents that prevented these materials from penetrating into the micropores. High moisture retention and low bulk density were related to the presence of amorphous silica because the particles have a spongy arrangement (90% is water and 10% is solid). This is a possible explanation for the high compressibility of the material, process related to the sinking of constructions.
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