The evaluation of the effects of high temperature on diatomite added mortar

In this study, the high temperature endurance of diatomite substituted mortars which were made by adding Ankara Kızılcahamam region diatomite (90 µm) into CEM I (Portland Cement 42, 5 R) with the rate of 0, 5, 10, 15%. Diatomite substituted mortars samples were cured for 28 and 90 days; they were heated to 20, 150, 300, 500 and 700 °C and cooled with air and water. The experimental of ultrasonic pulse velocity, flexural strength and pressure resistance of diatomite substituted mortar samples were performed, 28th and 90th day values of them were statistically evaluated. According to 90 days long ultrasonic pulse velocity values; CEM I (Portland Cement 42,5 R) enhanced the ultrasonic pulse velocity values of diatomite substituted cement 20.82% at 20 °C and 700 °C, CEM I (Portland Cement 42,5 R) has no changing effect on 10% diatomite substitute at 300 °C, it decreased the ultrasonic pulse velocity values for 2.48% at 150 °C and 500 °C. Considering the cooling methods, the ultrasonic pulse velocity values of mortar samples which were cooled in water were better than the ultrasonic pulse velocity values of mortar samples which were cooled with air. According to 90 days long flexural strength values; CEM I (Portland Cement 42,5 R) effects on cement were to decrease the strength of 10% diatomite substitute at 20 °C, 150 °C and 300 °C by 2.32%, 7.43% at 500 °C for 15% diatomite substitute and to enhance by 79.99 at 700 °C for 5% diatomite substitute. According to cooling methods; the development rates of air cooled mortar samples were higher than those of water cooled samples. According to 90 days long pressure resistance values; CEM I (Portland Cement 42,5 R) enhanced the values of cement by 20.18% at 20 °C, 150 °C, 300 °C and 700 °C for 10% diatomite substitute and by 17.37% at 500 °C for 15% diatomite substitute. According to cooling methods; the flexural resistance enhancement rates of samples cooled in air were higher than those of samples cooled with water.Key Words : High temperature, Mortar, Cement, Diatomite