Department of civil engineering, University of Guilan
Abstract
One of the most important aims in stabilization of sandy soils is to increase the normal stiffness. Cementation through mixing or grouting is a common method for treatment of sands. However, due to the use of nanotechnology in stabilization of soils, the addition of nanoscale materials has also attracted the attention of researchers and engineers. In this study, the effect of adding nano-materials with pozzolanic properties on the stiffness of cemented and uncemented uniform sand is discussed. For this purpose, different percentages of nano-silica and nano-alumina (up to 1.2%) were mixed with uniform sand, as well as sand with 3 and 6% cement, and one-dimensional settlement of compacted samples was examined under vertical loading using the oedometer device. The results of experiments and the scanning of electron microscopy images showed that addition of nano additives, in addition to filling a portion of nano pores with nanoscale materials, can be increased the hardened phase of cement paste by consuming calcium hydroxide and producing more CSH gel due to the pozzolanic property and the high specific surface area. It therefore effectively increases the unconfined stiffness of soil. As a result, a small amount of this type of material can play a significant role in reducing the vertical deformation of the stabilized soil.
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