Investigation Of The Effect Of High Temperatures And Different Cooling Conditions On The Concrete With Calcerous Aggregates

Abstract

In this study, it was investigation the physical and mechanical properties of the concretes produced with calcareous aggregate under high temperature applications and different cooling conditions. For this reason, C25 class concrete has been produced by using calcareous crushed stone aggregate, CEM I 42.5 R cement, super plasticizer admixture and water as additional material. Fresh and hardened concrete tests were conducted on produced concrete samples. Concrete samples were casted to 1000x1000x100 mm(3) rectangular prisms and core samples were extracted from these prisms other 28 days. To core samples 20 (Reference), 100, 200, 300, 400, 500, 600, 700, 800 and 900 degrees C temperature were applied. These samples were cooled using water and air separately. Ultrasound and uniaxial compressive strength test were performed on these samples. As a result, it has been determined that the quality and the strength of the concrete decrease as the temperature increases; that the compressive strength of the samples cooled in water is higher than the ones cooled in air; that the quality of the concrete has not changed which was measured by the ultrasound device according to the cooling type; that the compressive strength of the concrete has decreased 50% when compared to the reference sample in 400 degrees C; and 82% decrease has been detected in the compressive strength in the temperatures higher than 700 degrees C since CaO(2) + H(2)O -> Ca(OH) (2) occurs.