Mechanical properties of weakly bonded cement stabilized kaolin

Soil mixing with cement is one of the fastest growing specialties in many coastal and offshore areas and is becoming means of improving poor ground conditions. The engineering properties of clay soils can be enhanced by addition of cement, thereby producing an improved construction material. While this ground improvement technique is gaining popularity, the strength-deformation behaviour over the long term and the soil structure of the clay-cement mixture are not well understood. This paper aims to investigate the mechanical behaviour of cement-stabilized Kaolin with Portland cement. An extensive laboratory program was carried out to determine the mechanical characteristics of kaolin-cement, with some brief examination of the effects of curing environment. Results show that while cement increases strength, it also reduces axial strain required to achieve failure under drained conditions. Furthermore, when the cement content is 5 percent or less, kaolin-cement may not improve with time after 28 to 56 days; this may be partially due to softening during curing. Addition of cement increases the degree of flocculation of the clay particles; this is associated with an increase in pH of the pore wate However, the pH decreases over time. The formation of various new reaction products has been identified using scanning electron microscopy (SEM) technique.