COMPACTING CHARACTERISTICS OF ALUMINUM-FLY ASH POWDER MIXTURES

Aluminium-fly ash powder mixtures containing 5-20 wt % fly ash were pr epared using both precipitator (solid) and cenosphere (hollow) fly ash particles. These were compacted at pressures ranging from 138-414 MPa . Spring back, densification parameter, green density, green hardness and green strength of the compacts were determined as a function of co mpacting pressure and weight per cent of fly ash. It was observed that the spring back, green density and green strength of the compacts inc reased with increasing compacting pressure. Green density, green stren gth and green hardness of the compacts decreased, and the spring back increased, with increasing weight per cent of fly ash particles, the c enosphere particles leading to a higher spring back as compared to sol id precipitator particles. At compacting pressures of the order of 345 MPa, the solid fly ash particles generally remained intact, and well distributed in the matrix, but the hollow cenosphere particles collaps ed, and outer shells were present in the matrix in layered forms.