Residual compressive strength of Iraqi-gypsum subjected to elevated temperature exposure

الملخص EN

The effect of elevated temperate exposure on the compressive strength of ordinary gypsum and plaster of Paris has been studied in this research.

The gypsum test specimens were subjected to six temperature levels of 100, 200, 300, 500, 700 and 900 oC with three different exposure periods of 0.25, 0.5 and 1 hour.

Results of 111 specimens for two types of gypsum with two cooling conditions having compressive strength ranging from 15 to 0 MPa were presented.

These results showed that, the compressive strength of the specimens at temperature up to 100 oC exhibited a slight increase as compared with reference values.

But all gypsum specimens suffered a significant decreases in compressive strength when exposed to 500 oC and above.

After a period of 0.50 hour, the exposure period was seen to have a slight effect on the residual strength of ordinary gypsum except at 900 oC.

The results also show that no residual strength was observed at 500 and 900 oC for the plaster of Paris and ordinary gypsum specimens respectively.

On the other hand, water cooling was adversely affects on strength as compared with air cooling.