Author : Youssef Awad
CoAuthors : Mohamed Kohail, Mohamed A. Khalaf
Source : International Journal of Scientific & Engineering Research
Date of Publication : 07/2018
Abstract :
Concrete is more durable against fire than other construction materials. However, high temperature has deteriorating effects on
concrete mechanical properties. Decrease of strength at higher tempera¬ture can be associated with various reasons, such as micro-and
macro-cracks in concrete, volume expansion of coarse aggregates and the deterioration of calcium silicate hydrate (C-S-H) gel in the
cement paste. Behavior of concrete subjected to fire depends on its mix properties, fire temperature and duration, dimensions of the
structural elements, thickness of the concrete cover, fire extinguishing method (which control the rate of cooling) and the surface area to
volume ratio of different structural elements. The main objective of this research is to study the effect of four different extinguishing
methods on the ultimate strength of 30 reinforced concrete columns subjected to fire. The tested columns are of different surface area to
volume ratios. Non-destructive tests (Core & Ultrasonic pulse velocity tests) were used to estimate the deterioration extent of concrete
subjected to fire. Results of the experimental study had shown that by increasing the surface area to volume ratio or by increasing the
cooling rate, the ultimate strength of RC columns decreased considerably. A mathematical model was developed to estimate the ultimate
strength of RC columns subjected to fire in order to decide whether these columns deserved repair and strengthening or not. Results of the
mathematical model and the obtained experimental results were compared together to evaluate the accuracy of the proposed model
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