FATIGUE-CRACK GROWTH IN FLY-ASH COMPACTS

Fatigue characteristics of flyash compacts are studied within the fram ework of fracture mechanics. Also, a test method is proposed to invest igate the fatigue behaviour of flyash compacts. The curves of stress v ersus number of cycles to failure for flyash with moisture contents of 0.1% and 0.3% indicate that flyash compacts possess fatigue character istics. The da/dN-DELTAK and a-N relationships have been deduced for m oisture content 0.1% from the principles of fatigue crack growth. The results show that the rate of fatigue crack growth in flyash compacts obeys the Paris power law equation, and the fatigue properties of flya sh compacts can be characterised as falling between those of metals an d ceramics.