Effect of nano calcium carbonate (nano CaCO<sub>3</sub>) on the strength and consolidation properties of clayey sand soil
Mostafa Mohammadi, Mehdi Khodaparast, Ali M. Rajabi
Abstract
Nanotechnology is extensively used in engineering to improve systems, characteristics and standards. Various techniques can be used for soil improvement in road embankment and geotechnical engineering. The present study examined the effect of nano calcium carbonate (nano-CaCO3) on clayey sand soil using uniaxial and consolidation tests on specimens containing 10%, 20% and 30% kaolinite and bentonite, and 0.3%, 0.7%, 1.1% and 1.5% nano-CaCO3 at curing times of 7, 14 and 28 days. The results showed that mixtures containing 10% and 20% clay plus 0.7% nano-CaCO3, and specimens with 30% clay and 1.1% nano-CaCO3, exhibited optimal UCS and consolidation properties. XRD patterns indicated an increase in the intensity of the phases (calcium silicate hydrate, kaolin, calcite, etc) after the addition of nano-CaCO3 to the soil. SEM micrographs showed better filling of voids after the addition of nano-CaCO3 to both clay types. The amounts of these products were higher in the bentonite specimens .