Clay Soil Stabilization Research Articles

Soil stabilization by multivalent cations : Matsuo, S; Kamon, M Proc 10th International Conference on Soil Mechanics and Foundation Engineering, Stockholm, 15–19 June 1981V3, P735–738. Publ Rotterdam: A. A. Balkema, 1981

Stabilization of soft clay soils is one of the most important and difficult problems in soil engineering, so that many methods have been recently developed in Japan. In this paper, a new stabilization method of soft clay soils using multivalent cations is introduced. Trivalent cations, e.g. Fe3+ and A13+ are selected, and their reactions with clay particles are investigated. The principle is a hardening of clay particles due to the cation exchange effect and the physical adsorption of oxides. Regarding engineering properties of the treated samples, the shearing strength sharply increased and low compressibility was obtained. The beneficial effects of this treatment are clarified not only for engineering properties but also for microscopic mechanisms (ionization process and aggregating phenomenon). The improved properties of soft clays are sufficient to be applicable to real construction projects. (TRRL)

The Influence of the Mineral Content of Clays on their Stabilization by Cement

Stabilization of clay soils can be brought about by mixing with cement. This results in the formation of gelatinous products within the interstices of the soil which crystallize as the hardening process develops. The strength of the stabilized soil is developed as the cement hydrates. The various clay minerals in a clay soil influence the ease with which it can be stabilized with cement. Kaolinite appears to have little effect on the hydration of cement and hardening proceeds normally. Well organized illite may be regarded as inert as far as cement stabilization is concerned. By contrast clay minerals with an expansive lattice, notably montmorillonite, have a profound influence on the hardening of cement. Clay soils with an appreciable content of such minerals will, however, respond to cement stabilization if pre-treated with lime. Certain components found in clays, particularly organic matter and sulphates, retard or prevent proper hydration and therefore prove deleterious to soil-cement mixtures.

Stabilization of Clay Soils Against Erosion Loss

AbstractAccelerated soil erosion from construction sites and the resulting increase in downstream sediment load constitute a significant environmental problem. Laboratory studies indicate that small percentages of hydrated lime or of Portland cement will stabilize clay soils against rainstorm erosion by preventing particle detachment. Coordinated measurements of the size distribution of water-stable aggregates, of pore size distribution by mercury porosimetry and of microstructure by scanning electron microscopy and energy dispersive X-ray spectrometry were used to clarify aspects of the mechanisms responsible for the development of erosion resistance. Attainment of such resistance was marked by aggregation of a significant part of the clay into water stable aggregations of the order of several mm in size and of minimal change in porosity and pore size distribution on exposure to the test rainstorms. At least some of the clay particles in the aggregations appeared to be partly converted to calcium-bearing reaction products and formation of the “reticulated network” variety of calcium silicate hydrate gel linking adjacent particles was demonstrated.

A cids as chemical stabilizers of clay soils

1. In the acid stabilization of clay soils the aluminosilicate nucleus of the clay minerals is attacked. This process is accompanied by the escape of primarily the aluminum ion from the crystal lattice and the formation of depolymerized silicic acid. As the acid medium is neutralized to pH>3, the latter is condensed into an acid, highly hydrated silica gel, which cements the soil.