Study on the Compressive Behaviour of Sustainable Cement-Based Composites under One-Hour of Direct Flame Exposure

Abstract

Fire is a significant threat to human life and civil infrastructures. Builders and architects are hankering for safer and sustainable alternatives of concrete that do not compromise with their design intent or fire safety requirements. The aim of the present work is to improve the residual compressive performance of concrete in post-fire exposure by incorporating by-products from urban residues. Based on sustainability and circular economy motivations, the attention is focused on rubber tire fly ash, aged brick powder, and plastic (PET) bottle residuals used as partial sand replacement. The selected by-products from urban residues are used for the preparation of Cement-Based Composites (CBCs) in two different proportions (10% and 15%). Thermal CBC behaviour is thus investigated under realistic fire scenarios (i.e., Direct Flame (DF) for 1 h), by following the International Organization for Standardization (ISO) 834 standard provisions, but necessarily resulting in nonuniform thermal exposure for the cubic specimens. The actual thermal exposure is further explored with a Finite Element (FE) model, giving evidence of thermal boundaries effects. The post-fire residual compressive strength of heated concrete and CBC samples is hence experimentally derived, and compared to unheated specimens in ambient conditions. From the experimental study, the enhanced post-fire performance of CBCs with PET bottle residual is generally found superior to other CBCs or concrete. The structure–property relation is also established, with the support of Scanning Electron Microscopy (SEM) micrographs. Based on existing empirical models of literature for the prediction of the compressive or residual compressive strength of standard concrete, newly developed empirical relations for both concrete and CBCs are assessed.

Behaviour of steel beam subjected to the fire

“…To increase the fire resistance of structure is considered to do various methods of protection of beam section. Fire protection in various types of structures can be found in [5] or using flame retardants described here [6][7][8].…”

“…Analysing fire loaded structures 4 main groups of problems have to be solved: -Selection of the design fire scenario to describe the real expected load -Determination of the corresponding design fire -Calculation of temperature development in structural elements -Calculation of the mechanical behaviour of structure subjected to fire Various researcher were focused on the structural response under the fire load. Louter et al [3] conducted research on structural response of fire-exposed laminated glass beams, Vedrtnam et al in [4] studied the compressive behaviour of sustainable cement-based composites under one-hour of direct flame exposure, Bedon studied fire resistance of in-plane compressed log-house timberwalls with partial thermal insulation in [5]. Behaviour and design of eccentrically loaded hot-rolled steel SHS and RHS stub columns at elevated temperatures was described in [6], Non-linear analysis of composite beam subjected to fire was done in [7].…”

Mechanical Properties of Concrete Using Recycled Aggregates Obtained from Old Paving Stones

“…Vedrtnam et al [22]. studied the response of cement-based composites under direct flame conditions, demonstrating improvement in the residual compressive strength compared to conventional concrete after the thermal exposure.…”

Novel Methods for Post-Fire Self-healing of Concrete

“…The inclusion of polymer bers, for instance, has shown promise in preventing thermally induced explosive spalling, where the bers melt around 170 ºC, creating pathways for steam migration and reducing pore pressure within the matrix [10]. Prior research has demonstrated that incorporating processed PET residuals can enhance the re retardancy of concrete samples [11]. Nevertheless, challenges persist in achieving superior post-re load-bearing capacity in re-resistant concrete.…”