Yüksek sıcaklık uygulanan çimento harçlarının farklı soğutma koşullarındaki bazı fiziksel özellikleri

Bu çalışmada, yüksek sıcaklık etkisi altında kalmış çimento harçlarının farklı soğutma koşullarında eğilmedeçekme dayanımı, basınç dayanımı ve boşluk oranı değişimi incelenmiştir. Çimento harç örneklerine 100, 300,500, 700 ve 900 °C sıcaklıklar uygulanmıştır. Soğutma işlemi havada ve suda olmak üzere iki şekildegerçekleştirilmiştir. Laboratuar ısısına kadar soğutulan örneklerin eğilmede çekme dayanımı, basınç dayanımı veboşluk değerleri belirlenmiştir. Farklı sıcaklıklar ve farklı soğutma şartlarında veriler kullanılarak çoklu doğrusalregresyon modelleri oluşturulmuştur. Harç örneklerinin eğilmede çekme ve basınç dayanımlarında 100 °C’de birmiktar artış olmasına rağmen bundan sonraki sıcaklıklarda sıcaklık ortalamasına bağlı olarak azalma eğilimigörülmüştür. Soğutma koşullarına göre; 500 °C’deki eğilmede çekme dayanımının havada soğutulmuşörneklerde % 29, suda soğutulmuş da ise % 58; basınç dayanımının havada soğutulmuş örneklerde % 10, sudasoğutulmuş da ise % 35 oranında azaldığı görülmüştür. Aynı zamanda boşluk oranının havada soğutulmuşörneklerde % 3.3, suda soğutulmuş örneklerde ise % 9 oranında arttığı görülmüştür.

Physical properties of cement mortars exposed to high temperature in various cooling conditions

Tensile strength of bending, compressive strength and porosity rate change of cement mortars exposed to hightemperature were examined in this study. 100, 300, 500, 700 and 900 C° temperatures were applied to cementmortar samples. Cooling process were implemented in two ways as in air and in water. Tensile strength ofbending, compressive strength and porosity rates of samples, which were cooled to laboratory temperature, weredetermined. Multiple linear regression modeling were made up by using the data from different temperatures andcooling conditions. Although there is an increase in tensile strength and compressive strength of mortar samplesin 100 C°, after this temperature it was seen that there was a decrease tendency according to averagetemperature. According to cooling conditions it was observed that the tensile strength of bending of the samplesthat were cooled in air were decreased 29%, and that were cooled in water were decreased 58%; the compressivestrength of the samples that were cooled in air was decreased 10%, and that were cooled in water were decreased35%. Furthermore, it was observed that porosity rate of the samples that were cooled in air were increased 3.3%,and that were cooled in water were increased 9%.

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