Effect of Fire Exposed on the Behavior of Reactive Powder Concrete Columns under Concentric Compression Loading

Master's Thesis from the year 2017 in the subject Engineering - Civil Engineering, grade: 96, University of Babylon (University of Babylon / College of Engineering), language: English, abstract: With growing of the structural design requirements for higher strength materials in applications where member size is governing factor in design especially in construction of columns in high-rise buildings, reactive powder concrete (RPC) as a king of ultra-high performance fiber reinforced concrete is catching more attention nowadays due to its extraordinary strength and durability properties. In addition to the developments in concrete technology, the fire engineering design of buildings made from this concrete has become commonplace. Accordingly, the major component of this Thesis aims to contribute new knowledge with respect to the understanding of the fire behavior of concentrically loaded reinforced (RPC) columns. The first part of this research is the experimental investigation of the behavior of reactive powder concrete (RPC) and normal strength concrete (NSC) columns exposed to fire flame from 2-adjacent sides. Forty-eight reduced-scale models of RPC and NSC column specimens had a dimensions of (100 100 900 mm) with longitudinal reinforcement of (4 6mm) were concentrically loaded up to failure at age of 56 days prior to and later on fire burning to analyse the influence of some determinant parameters in improving fire resistance of these columns. While the second part is a three-dimensional finite element (FE) modeling of the reinforced RPC columns in ABAQUS using a four-nodded tetrahedral element capable of coupled thermal displacement analysis of the fire exposure. Fire-induced spalling is also presented based on pore pressure calculations in concrete. The obtained results of this study showed that the load carrying capacity of"e; RPC columns is slightly increased after burning at 200 C. While it is decreased significantly after exposure to fire temperatures of (400 and 600 C). RPC columns lost about (39 to 45%) of their load carrying capacity after burning at 600 C. On the other hand, NSC columns provide excellent fire resistance compared with RPC columns in which the reduction was only about (15 to 24%) after burning at the same temperature level. The effect of reducing tie spacing for improving the fire resistance of RPC columns had a slight influence at 400 C fire temperature. While at 600 C, the effect was insignificant. In addition, the effect of increasing concrete cover was nearly negligible and the load carrying capacity of RPC columns with different concrete covers became close to each other at higher fire temperature levels.