Compacted black cotton soil treated with cement kiln dust as hydraulic barrier material

Abstract

Laboratory tests were conducted on black cotton soil treated with up to 16% Cement Kiln Dust (CKD) by dry weight of soil to assess its suitability for use in waste containment application. Specimens were prepared at molding water contents -2%, 0%, +2% and +4% of the optimum moisture content at the compactive energy levels of British Standard Light (BSL) and West African Standard (WAS). Index properties, hydraulic conductivity (k), volumetric shrinkage strain (VSS) and unconfined compressive strength (UCS) tests were carried out. Results obtained showed slight changes in index properties. Hydraulic conductivity values recorded at both BSL and WAS produced satisfactory results that met the regulatory 1x10 -9 m/s requirement at all treatment levels. The UCS values after 4% CKD treatment especially at WAS compactive energy level met the minimum regulatory value of 200kN/m 2 for shear strength. VSS values recorded met the regulatory requirement of less than 4% volumetric shrinkage strain at 16% CKD content for BSL and 12 and 16% CKD contents for WAS energy level. The overall acceptance zone for CKD treated black cotton soil was achieved at 12 and 16% cement kiln dust content for specimen prepared at molding water content range of 16.7-21.6% and 17.2-19.3 % respectively.

The Mechanical Properties of Fly-Ash-Stabilized Sands

“…This is predicted to be because of the self-hardening of the mixture between the fly ash and sand particles. Previous research conducted by Gay [21][22][23][24][25][26][27][30][31][32]47,48]. In more detail, Jalali et al (1997) confirmed that the delayed improvement in the strength of stabilized soil was strongly dependent on the curing temperature [32].…”

“…The delay in the strength improvement at the initial stage is the natural behavior of FA as a binder. Sufficient time is needed for completion of the pozzolanic reaction in establishing cementitious and pozzolanic gel [21][22][23][24][25][26][27][30][31][32]38,47,48].…”

“…These chemical reactions dissociate the lime (CaO) in the fly ash and establish cementitious and pozzolanic gels consisting of calcium silicate hydrate (CSH) gel and calcium aluminate hydrate (CAH) gel, as described in Equations (1) to (4). Consequently, the fly ash will bind to soil particles and increase the strength and stiffness of that soil [21][22][23][24][25][26][27].…”

Determination of Optimum Cement Content for Stabilization of Soft Soil and Durability Analysis of Soil Stabilized with Cement

“…Time-strength development is crucial in the study of strength characteristics of soils treated with stabilizers as the structure of such materials evolves with time due to continuing hydration/ pozzolanic reactions ( [7], [8], [9], [10]). To illustrate the strength evolution soil specimens treated with 2%, 4%, 6%, 8% and 10% cement, the stress-strain response was recorded for each of the mixtures which were cured for 0, 7, 14 and 28 days to produce the stress-strain curves.…”

Stabilization of Highway Expansive Soils with High Loss on Ignition Content Kiln Dust

“…They are so named because of their colour and suitability for growing cotton. Black cotton soils have colours ranging from light grey to dark grey and black [2]. Black cotton soils are confined to the semi----arid regions of tropical and temperate climatic zones and are abundant where the annual evaporation exceeds Black cotton soils occur in continuous stretches as superficial deposits and are typical of flat terrains with poor drainage.…”