Thermal Analysis and Fire Property Quantification of Crumb Rubber and Plastic Eco-Aggregates for Sustainable Construction

Abstract

With a drive for sustainable construction, various products are being introduced to promote recycling, but often their properties relation to behaviour in fire are not known. In this paper, the fire performance of crumb rubber and a plastic eco-aggregate, called RESIN8, were assessed. Various tests, including cone calorimeter, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), were conducted. These are supplemented by numerical calculations and the Coats–Redfern kinetic model to quantify the thermal and fire properties of these materials. Cone calorimeter tests were conducted at 35 and 50 kW m⁻², while the critical heat flux (CHF) values were determined using a range of irradiance levels. Time to ignition (TTI), heat release rate (HRR), peak heat release rate (pHRR), and thermal fire hazard parameters were quantified. Both materials were classified under the high thermal fire hazard class. The peak thermal decomposition rates occurred at 365°C (single peak) for CR and at 435°C and 550°C (two peaks) for RESIN8. The calculated activation energy values were 66.7 kJ mol⁻¹ for crumb rubber and 55.1 and 43.9 kJ mol⁻¹ for RESIN8 in the first and second stages, respectively. These eco-aggregates could pose a significant thermal fire hazard, in the recycling facility during and after the recycling process, as well as when stored in bulk and when incorporated in large quantities in construction systems. Further investigation is crucial for understanding the effect of incorporating these eco-aggregates within masonry and concrete systems from a fire safety perspective.