Engineering characteristics of soil stabilised with saw dust ash and cement

The study herein investigates the performance of Saw Dust Ash (SDA) in combination with cement for soil stabilisation. Performance of SDA is studied with respect to compressive strength, shear strength, penetration and deformation responses. For a certain cement content, the compressive strength reaches a maximum value with the increase of SDA and the corresponding SDA content is defined as the optimum content. Optimum SDA content varies within 6-12% based on the percent of cement added. When optimum amount of SDA is added, 28 days' compressive strength of 2406-5625 kPa was achieved for varying amount of cement (3-7%). The mechanical response is illustrated using microstructural observations. Results from direct shear tests revealed that with the inclusion of 6-15% SDA with cement, improved shear strength parameters (cohesion, angle of internal friction) can be obtained; an angle of internal friction as high as 40 degrees was achieved herein. Compression index can be reduced by 32-41% compared to unstabilised soil if optimum amount of SDA-cement is added. It is concluded that considering compressive strength, shear strength, penetration resistance and compressibility, SDA can effectively be used along with cement for stabilisation of clay soil.