Behaviour of high-performance concrete at high temperatures: some highlights

Abstract

High-performance concrete (HPC) is now used routinely in building and civil structures. . The development of using HPC in structural applications and the growing need for justification of the fire resistance has led several laboratories to carry out research on properties at high temperature. This letter presents some main aspects related to physicochemical changes, thermal properties and mechanical properties for HPC at high temperature. It introduces a State of The Art prepared by the RILEM Technical Committee 227-HPB (Physical properties and behaviour of HPC at high temperature) and titled "Behaviour of HPC at high temperatures". This State of the Art will be published in the near future.

Engineering properties and flexural performance of carbon nanofibers enhanced lightweight cementitious composite (CNF-LCC)

“…The maximum values for ceUHPC, CNF-LCC, and LCC range from 1322 to 1400 J/(kg•K) are very close. The additional heat required to drive off water is proportional to the water content in concrete (Nguyen et al, 2009), which is critical to the maximum specific heat at a temperature under 200 ℃ (Pimienta et al, 2017). The maximum specific heat value of the three samples in Figure 4.6 is similar with HSC from Kodur and Sultan (2003) but lower than foam concrete in Othuman and Wang (2011) because the water-cement ratio of the former is similar as in this study but that of the latter is higher.…”

“…The first step at about 150 ℃ corresponded to the removal of free water and dehydration of ettringite Fernandez, 2004, Khoury, 2008). In addition, the loss of bound water and dehydration of C-S-H started from about 100 ℃ (Pimienta et al, 2017). Between 150 and 650 ℃, gradual and slow mass loss was observed.…”

Compressive Strength of Rapid Sulfoaluminate Cement Concrete Exposed to Elevated Temperatures

“…The average thermal expansion coefficient of the quartz river sand and limestone gravel used for the experiments at the different temperatures were also calculated [23,24]. Figure 6 shows the stereo microscopic appearance image of the SACC samples immediately after removal from the furnace, following exposure at the different temperatures for 4 hrs.…”

Properties of High-Performance Concretes made of Black Sand at High Temperature

“…The chief effects of fire are summed up as a loss of strength, spalling and cracking, and destruction of the bond in the interfacial transition zone (ITZ) between the cement paste and the aggregates, similar to the piecemeal disintegration of hardened concrete [15]. Their probability of occurrence increases within the hardened cement paste hydrated components, yet additionally within the aggregates relying on the type of rock concerned [16], except for the crystal transformations occurring mostly within the aggregates. Thus, the processes involve the so-called degradation responses of cement paste, which are reactions that achieve a progressive breakdown within the concrete structure.…”