One-dimensional compression and swelling of compacted fly ash

The aim of the paper is to prove that the compressibility and swelling of compacted fly ash in both unsaturated and fully saturated conditions are dependent on the moisture content at the compaction and on the compaction energy, as in the case of cohesive soils. The studies have been conducted on samples compacted at various water contents in conventional oedometers and the Rowe hydraulic consolidation cell and in California bearing ratio moulds (swelling tests). The one-dimensional compressibility of saturated fly ash is much higher than that of unsaturated fly ash. Deformation of unsaturated samples increases with moisture at compaction, and the samples compacted with greater effort are less compressible. The consolidation of the saturated samples decreases with their moisture content at compaction and at the reduction of the compaction energy. The swelling of ash samples decreases as the moisture during compaction increases and when compaction energy is lower. The highest swelling was obtained for the fly ash with the highest optimum water content.