Development of fly ash–based spray-applied fire-resistive materials

Abstract

Spray-applied fire-resistive materials (SFRMs) are one of the most commonly used passive fire protection materials due to their low thermal conductivity, lightweight, cost-effectiveness, and ease of application. SFRMs generally contain gypsum or Portland cement binder, mineral fillers and fibres. Binder materials account for approximately 50 to 75 wt.% of the total materials used to produce SFRMs. Consequently, SFRM production contributes significantly to greenhouse gas emissions. To minimise this effect, fly ash has been used in hybrid alkaline cement and blended cement as an alternative to cement clinker for making concrete. The present study investigates the feasibility of using industrial by-products and wastes such as fly ash and expanded glass made from recycled glass to manufacture SFRMs with the aim of reducing the environmental effects and consumption of natural and non-renewable resources. This study compared the developed hybrid alkaline cement (HAC) and fly ash blended cement (FAC) binders in terms of their material properties, such as flow, setting, compressive strength and the microstructure of the hardened pastes. The environmental impact and costs of the HAC and FAC binders were also analysed and compared with the reference ordinary Portland cement (OPC) binder to assess the benefits of using fly ash in SFRM binders. Compared with OPC, FAC can reduce carbon emissions by 68.4%. Additionally, HAC use can further reduce carbon emissions by 16.1%. Among the three binders, FAC has the lowest cost 35.5% and 10.4% lower than the costs of OPC and HAC, respectively. Given these overall benefits, the present study selected FAC to make the binder for SFRMs. This research confirms the practicality of using fly ash and expanded glass in SFRM development and affirms the ensuing benefits in terms of reducing environmental impact and costs. The developed high-density SFRM exhibits excellent fire resistance and thermal properties compared with commercially available SFRMs. The proposed FE heat transfer model can be used to accurately predict fire resistance ratings and provide safe designs for fire protection.

Date of Thesis submission	2023
Original language	English
Awarding Institution	Western Sydney University
Supervisor	Zhong Tao (Supervisor), Zhu Pan (Supervisor), Md Kamrul Hassan (Supervisor) & Utsab Katwal (Supervisor)