Experimental study on the spalling behaviour of ultra-high strength concrete in fire

Abstract

High strength construction materials are now attractive owing to their economic and architectural advantages. The higher the material strength, the smaller member size is required. Ultra-high strength concrete (UHSC) encased columns are being developed for the erection of high-rise buildings due to their higher load bearing capacity and smaller cross section size compared to normal strength concrete encased columns. When the UHSC is subject to elevated temperature, explosive fire-induced spalling is more often observed than in normal strength concrete. The consequence of spalling could cause serious life loss and damage to the close key infrastructure. Spalling is mostly due to the UHSC increased density, lower permeability and brittleness. Most of the previous studies show that polypropylene fibres have been found * Corresponding author.

Flexural Behavior of Ultra-High-Performance Fiber-Reinforced Concrete Beams after Exposure to High Temperatures

“…In other words, steel fiber could reduce the risk of spalling caused by thermal stress, but the steel fiber bridge could not completely resist the increase in pore pressure. This is consistent with the findings of Du et al [ 45 ] and Sciarretta et al [ 46 ].…”

“…In other words, steel fiber could reduce the risk of spalling caused by thermal stress, but the steel fiber bridge could not completely resist the increase in pore pressure. This is consistent with the findings of Du et al [45] and Sciarretta et al [46]. Figure 16 shows that under the action of high temperature, part of the ettringite and C-S-H gel in the sample was destroyed and dispersed.…”

“…In other words, steel fiber could reduce the risk of spalling caused by thermal stress, but the steel fiber bridge could not completely resist the increase in pore pressure. This is consistent with the findings of Du et al [45] and Sciarretta et al [46]. Generally speaking, when fiber-reinforced concrete suffers from fire, the thermal deformation of its components will cause the micro-cracks at the interface between cement paste and aggregate and between cement paste and fiber to open and expand [32].…”

Behavior of Ultra-High Strength Concrete Beams

“…Recently, the commercial usage of HSC increases progressively due to outstanding engineering properties that offers and the life cycle costperformance ratio [2][3][4][5]. HSC possesses prodigious benefits, including high compressive strength and elastic modulus, and vast economic benefits brought by reducing the dimension of structure sections comparing with the ordinary concrete [6]. Therefore, a large number of HSC is utilized for tall buildings and long-span structures.…”

“…This concrete consists of portland cement, fine sand or quartz, silica fume, water reducing admixture and steel fibers [5]. UHSC could be economically prepared by concrete plants all over the world owing to availabilities of additives and admixture such as silica fume and water reducing admixture [6,7]. The development of UHSC is one of the safety features in nuclear reactors.…”