EFFECT OF TEMPERATURE ON PHYSICAL AND MECHANICAL-PROPERTIES OF CONCRETE CONTAINING SILICA FUME

Fire is one of the natural hazards which attack building construction. The damage in buildings which continuously exposed to fire are caused due to its high temperature. Thus the effect of high temperatures on physical and mechanical properties of concrete was investigated. In th is study ordinary Portland cement has been partially replaced by ratio s of silica fume. The heat treatment temperature varied from 100 to 60 0 degrees C by increments of 100 degrees C for three hours without any load. Concrete specimens were treated at each temperature level. The specimens were heated under the same condition for each temperature le vel. Comparison between physical and mechanical properties during heat treatment were investigated. All specimens were moist-cured for 28 da ys after casting. Tests were carried out on specimens cooled slowly to room temperature after heating. Results of this investigation indicat ed that the replacement of ordinary Portland cement by 10% silica fume by weight improved the compressive strength by about 64.6%, but repla cment of ordinary portland cement by silica fume by ratios 20 and 30% improved the compressive strength by only 28% at 600 degrees C. This c ould be attributed to the additional tobermorite gel (CSH phase) which formed due to the reaction of silica fume with Ca(OH)(2).