Influence of the Manufacturing Method on the Fire Resistance of Geopolymer Materials Based on Mining Slag

Developing geopolymer materials based on waste is being promoted as an approach to reduce landfilling and encourage a circular economy. In this regard, high-performance geopolymers based on mining slag are developed for fire protection products, where the manufacturing method could have an influence. Accordingly, this paper assesses the fire resistance performance of two geopolymer products based on the same slag but produced considering two different manufacturing processes (precast and 3D printed), mainly focused on their use for tunnels. Furthermore, it studies other fire resistance evaluation methods (laboratory tests at different scales, in-situ tests, and computer based simulations), identifying their suitability for product development or research phases. On the one hand, results show that the production method affects the fire resistance performance since tested geopolymers reveal different thermal transmittance and mechanical behavior in prolonged or extreme fire exposure due to the diverse nature of the geopolymer material itself the first one is ductile material while the second a brittle material. In this sense, the 3D printed material shows a better thermal performance, but this can be significantly affected by the fastening configuration used. On the other hand, a step-by-step methodology based on the combination of the different fire resistance evaluation methods is presented to facilitate the product assessment during the various product development stages and for different system configurations or end-use applications.