Mechanical behaviour of remoulded fly-ash

Identification, oedometric and triaxial tests were performed on remoulded fly-ash samples, either in saturated or partially saturated state. The results of the saturated tests show that the behaviour of flyash is very similar to that of sandy silts and exhibit features characteristic of these soils : limited oedometric compressibility, overconsolidated-looking curves on drained triaxial paths, pore pressure curves presenting a peak on undrained triaxial paths, but also important differences, mainly low densities and a tendency to collapse. The small size of the particles and their physico-chemical properties makes them very sensitive to water. A simplified model is used to analize the part of negative pressure and its consequences on the strength and hardening of the material.