Comparing the Thixotropic and Lightly Solidified Hardening Behavior of a Dredged Marine Clay

C. M. Chan, H. Y. Yong

Abstract


When a soil is disturbed upon remolding, it may lose part or all of its strength. As time passes, the structural arrangement of the soil particles would be restored to a stable form and the soil would regain hardness under constant volume and water content. The process is known as “thixotropic hardening”. On another note, dredged marine soils of the fine-grained type can be reused as a backfill material instead of being disposed to the open sea. The rest period required for the relocated soil to regain strength and stiffness, i.e. thixotropic hardening, needs to be estimated precisely. For this purpose, a study on the phenomena of strength and stiffness gain by a dredged marine clay was carried out. The strength and stiffness improvement with time was measured using the vane shear and fall cone tests respectively. The clay was remolded at different water contents in multiples of the soil’s liquid limit (LL), namely 0.75LL, 1.00LL and 1.25LL, in order to evaluate the effect of initial water content on thixotropic hardening. A separate series of samples were prepared with light solidification using cement, to examine the possibilities of enhancing the soil’s improvement in a shorter rest period. The results showed the dredged marine clay can potentially be used as a backfill material for reclamation works, with lower initial water content and light solidification contributing to accelerated better performance


Keywords


thixotropic hardening; light solidification; dredged marine clay; undrained shear strength; cone penetration

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References


W. S. W. Salim, W. S., N. A. M. Noor, S. F. Sadikon, M. F. Arshad, N. Wahid, S. M. Salleh, “The preliminary investigation on the dredged marine sediment of Kuala Perlis as a potential brick material”, 5th International Conference on Environmental and Computer Science (ICECS2012), pp. 25-29, Thailand, 2012

S. Seng, H. Tanaka, “Properties of very soft clays: A study of thixotropic hardening and behavior under low consolidation pressure”, Soils and Foundations, Vol. 52, No. 2, pp. 335-345, 2012

S. Horpibulsuk, W. Phojan, A. Suddeepong, A. Chinkulkijniwat, M. D. Liu, “Strength development in blended cement admixed saline clay”, Applied Clay Science, Vol. 55, pp. 44-52, 2012

N. C. Consoli, L. Festugato, C. G. da Rocha, R. C. Cruz, “Key parameters for strength control of rammed sand-cement mixtures: Influence of types of portland cement”, Construction and Building Materials, Vol. 49, pp. 591-597, 2013

C. M. Chan, “Influence of mix uniformity on the induced solidification of dredged marine clay”, Environmental Earth Sciences, Vol. 71, No. 3, pp. 1061-1071, 2014

A. Y. Malkin, “Non-Newtonian viscosity in steady-state shear flows”, Journal of Non-Newtonian Fluid Mechanics, Vol. 192, pp. 48-65, 2013

J. Mewis, N. J. Wagner, “Thixotropy”, Advances in Colloid and Interface Science, Vol. 147-148, pp. 214-227, 2009

A. W. Skempton, R. D. Northey, “Sensitivity of clays”, Geotechnique, Vol. 3, No. 1, pp. 40-51, 1952

H. B. Seed, C. K. Chan, “Thixotropic characteristics of compacted clays”, ASCE Journal of Soil Mechanics and Foundation Engineering, Vol. 83(SM4), pp. 1427-1435, 1957

M. D. Braja, Fundamentals of Geotechnical Engineering. CENGAGE Learning, UK, 2013

C. M. Chan, A. Shamsuddin, “Sustainable geo-materials from agricultural and geo-wastes: Reborn and viva!”, Australian Journal of Basic and Applied Research, Vol. 7, No. 11, pp. 87-103, 2013

British Standard Institution, British Standard BS 1377-1: Methods of test for soils for civil engineering purposes. London, UK, 1990

H. Tanaka, H. Hirabayashi, M. Tatsuya, K. Hiroaki, “Use of fall cone test as measurement of shear strength for soft clay materials”, Soils and Foundations, Vol. 52, No. 4, pp. 590-599, 2012




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