Pond Ash Based Controlled Low Strength Flowable Fills for Geotechnical Engineering Applications

Granular materials are conventionally used as backfills behind retaining walls and many other filling applications. Normally, the backfills are compacted in layers at a relative compaction of not less than 95 % of the Standard Proctor unit weight at desired water content. Depending on the type of backfill material, suitable compaction equipments are selected for compacting the material. Usually, coarse grained materials like gravel, sand, Pond ash, crushed rock pieces and cobble are used as backfill materials. As a replacement to the conventionally used backfill materials, controlled low strength materials (CLSM or flowable fills) are also used, especially in areas where compaction equipments cannot be mobilized. This paper reviews the effective utilization of different types of ashes in flowable fill production and the main properties, advantages and applications in geotechnical engineering practice. Experimental results of a flowable fill made of a local Pond ash are also presented in this paper.