A Proposed Classification for Anisotropic Engineering Behaviour of Cement Treated Clayey Mixtures Related to Their Strength and Durability

 

Evangelos I. Stavridakis

B.Sc., M.Sc., Ph.D., F.G.S., Lecturer, Laboratory of Soil Mechanics and Foundation Engineering,Geotechnical Engineering Division, Department of Civil Engineering, Aristotle University of Thessaloniki , Thesssaloniki, Greec
stavrid@civil.auth.gr

ABSTRACT

The existence of some difficult soils (non - durable), often present difficulties in construction operations. However the engineering properties of these clay soils can be enhanced by the addition of cement, thereby producing an improved construction material.

In all practical cases, the primary ingredient necessary for stabilizing soils is calcium (% of cement). In addition to plasticity reduction, portland cement, by its inherent nature of producing strength - developing hydration products, provides improved strength and durability. Therefore the effectiveness of stabilization is based on the number of positions of exchangeable ions (mineralogical composition which is related to liquid limit) of a clay and the amount of liberated calcium ions from cement (% of cement, % of compaction and curing time) which influence the durability (bonding effect) and unconfined compressive strength (bearing capacity).

In an effort to characterize and study the suitability of silty - clayey soils for cement - stabilization both slaking and unconfined compressive strength tests were carried out on clayey - sand mixtures stabilized by cement, consisted of two types of clays, kaolin and natural bentonite.

Finally diagrams were prepared to study and classify the variation of slaking and strength of cement - stabilized clayey - sand mixtures (silty - clayey soils) due to compaction, curing time, cement percentage and liquid limit (of clayey - sand mixtures) and also to predict areas of efficient cement - stabilization.

Keywords: cement, clays, stabilization, classification, liquid limit, strength, durability.

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