PROPERTIES OF CEMENT-TREATED SOILS DURING INITIAL CURING STAGES

The engineering properties of cement-treated soils manufactured by the so-called Pipe Mixing Method and Super GeoMaterial (SGM) Method were studied. In these methods, clayey soils with high water contents are mixed with cement and used as fill material. Since the cement-mixed soils are transported through a pipeline, whose length at times exceeds 2 km, the properties of the treated soil during the initial stages of the hardening process are important. Bender element, vane shear and fall cone tests were performed to obtain such engineering properties as the shear modulus and the shear strength. The study revealed the following; 1) The minimum shear wave velocity of treated soils is detectable at around 2.8 m/s, corresponding to a shear modulus of about 12 kPa. 2) A linear correlation between the shear modulus and the shear strength exists even in the very early stages of curing, approximately G = 300 s, where G and s are the shear modulus and the shear strength, respectively. This relation is similar to that for natural clays. 3) The setting time observed for concrete is also apparent in cement-treated soil materials. 4) Fall cone tests comprise a useful and simple technique for measuring very low levels of shear strength.