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Performance of Polypropylene Concrete Subjected to Heating and Different Cooling Regimes



Fire is one of the most destructive powers to which a building structure can be subjected, often exposing concrete elements to elevated temperatures. The relative properties of concrete after such an exposure are of significant importance in terms of the serviceability of buildings. Unraveling the heating history of concrete and different cooling regimes is important for forensic research or to determine whether a fire-exposed concrete structure and its components are still structurally sound or not. Assessment of fire-damaged concrete structures usually starts with visual observation of colour change, cracking and spalling. Thus, it is important to know the effect of elevated temperatures on normal strength retention properties of concrete. This study reports the effect of elevated temperature on the mechanical properties of the 100mm concrete cube specimen with polypropylene fibres and cooled differently under various regimes. In the heating cycle, the specimen were subjected to elevated temperatures ranging from 2000C to 8000C, in steps of 2000C with a rest period of 1 hour at the reference thermal levels.. Then they were cooled to room temperature differently. The cooling regimes studied include, furnace cooling, air cooling and sudden cooling. After exposure to elevated temperatures and cooled differently, the weight loss, and residual compressive strength retention characteristics were studied. Test results indicated that weight and compressive strengths significantly reduce, with an increase in temperature and are strongly dependent on cooling regimes adopted

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