Environmental effect of partial replacement of cement by Flyash in cement stabilized soil blocks

Flyash, a residue of burning coal / lignite at thermal power stations, has generally been considered as a waste material, there is renewed interest in developing alternatives to disposal. One possible solution for this problem is to incorporate Flyash particles into cement-based materials. Utilization of Flyash should minimize environmental impact and maximize conservation of natural resources. In this study, use of Flyash wastes in producing cement stabilized soil blocks has been investigated. There are several parameters namely, the rate of added Flyash waste, the amount of cement used as stabilizer and block processing. The processing is exactly the same as per the soil stabilized blocks, except that fly-ash of specified quality, constitute an additional input material. The flyash is partially substituted for cement at 16% to 24% of total Cement content used, depending on the target Compressive Strength of the final product, thereby saving on costs. The Experimental investigation involves least investment and makes use of ordinary equipment with normal water spray curing. The blocks are good for making nonload-bearing walls or pre-cast blocks for nonstructural filler wall masonry. The use of Flyash as addition to cement paste show satisfactory results in mechanical properties, it has few desirable characteristics such as lower density and higher fracture toughness. The paper concludes that it is possible to significantly, improve the dimensional stability and performance of cement stabilized soil blocks to the extent, that they can be suitably used for construction of Pedestrian and low volume roads.