An investigation on thermal performance of wollastonite and bentonite reinforced intumescent fire-retardant coating for steel structures. (20th December 2019)

• Record Type: Journal Article
• Authors: Ahmad, Faiz; Ullah, Sami; Merican, Nurul Haswina bt H.; Oñate, Eugenio; Al-Sehemi, Abdullah G.; Yeoh, Guan Heng
• Is Part Of: Construction & building materials. Volume 228(2019)
• Publication Date: 2019-12-20
• Subjects: Wollastonite -- Bentonite -- Intumescent Fire-Retardant Coatings -- Thermal Degradation -- Structural Steel -- Transmission Electron Microscopy (TEM) -- XPS Analysis: Py-GC–MS; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2019.116734
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: The effect of Wollastonite and Bentonite on intumescent coating was investigated. IFRC5-2 presented back side substrate temperature 166 °C after 1-hour fire test. IFRC5-2 showed the char expansion 34% higher compared to the IFRC1-1. The highest residual mass 40.46% was also recorded by the IFRC5-2 coating. IFRC5-2 released less gaseous product concentration compared to IFRC1-1. Abstract: This research investigates the synthesis of new formulations of intumescent coating with improved thermal performance for steel structures. The coating formulations were based on the expandable graphite reinforced with wollastonite and bentonite. Ten samples of five formulations were synthesized by varying grinding time duration between 1 and 2 min. To analyse the substrate temperature of coated steel, fire test was performed according to ASTM-E119. The char morphology was observed by Field Emission Scanning Electron (FESEM) and Transmission Electron Microscopy (TEM). FTIR and X-ray Diffraction (XRD) test is conducted to analyse the composition of the residual char. The residual char mass was perceived by Thermogravimetric analysis (TGA) of the coating. X-ray Photo Electron Spectroscopy (XPS) was utilized for binding energy and elemental composition of the char. One-hour fire protection test showed 166 °C, the lowest substrate temperature of IFRC5-2 and 40.46% residual mass was obtained by TGA analysis. XRD analysis showed that residual char has aluminum borate and borophosphate and confirmed by functional group analysis using and FTIR. FESEM and TEM illustrated that char relates to hexagonal particles of wollastonite. XPS analysis of IFRC5-2 showed the carbon and oxygen contents were 41.40% and 51.20%. Pyrolysis-Gas Chromatography–Mass Spectrometry (Pyrolysis GC–MS) results showed IFRC-5 produced less concentration of the gaseous products compared to IFRC-C. The formulations developed by grinding solid ingredients for 2 min showed improved thermal performance compared with the formulation produced by grinding solid ingredients for 1 min. Longer grinding time and higher amount of filler improved the thermal properties of the intumescent coating.