Lime stabilisation of highly compressible surface from soils in ex-Lake Texcoco, Mexico

Abstract

Improving soil strength by physical and chemical methods is a common practice in geotechnical engineering. This study investigated the chemical stabilisation of soil with calcium oxide to modify the physical and chemical properties of clay materials — which can rapidly transform a material with poor mechanical properties into one with favourable properties for different surface working conditions and good short-, medium- and long-term geotechnical behaviours — the effects of this chemical stabilisation on the environment, and effects on the site and other regions beyond the airport construction polygon. The main advantages measured were the mitigation of the exploitation of borrow pits (27·6%), the use of natural materials from the site (81·1%) and the mitigation of the transport demand (11·1%). The analysed materials were lacustrine clay soils (cohesive soils) with low strength, high compressibility and moisture contents of 55, 100 and 170% from ex-Lake Texcoco in the basin of the Valley of Mexico. In this study, the authors performed Atterberg limits tests, compaction tests, unconfined compressive strength (UCS) tests, California bearing ratio (CBR) and expansion tests, Eades and Grim tests and quantitative chemical analyses by X-ray fluorescence and X-ray diffraction. The optimum lime contents for the analysed samples were 5 and 15%.