Assessing Pozzolanic Reactivity of Reclaimed Fired Clay Roof Tiles and Bricks in Presence of Ground Limestone

Due to drastic necessity to reduce cement and binder carbon footprint and because of increasing scarcity of traditional supplementary cementitious material, there is an increasing interest for non-traditional reactive materials with low CO₂ footprint, eventually coming from the circular economy. There are several emerging opportunities which need to be investigated before confirming their aptitude to substitute clinker, alone or in combination with other materials. Among these opportunities, reclaimed fired clay roof-tiles and bricks represent a good candidate not only because they were historically used by the antic Romans but also because they represent a significant part of demolition wastes. These materials, gathered from different locations in France with different ages, were chemically and mineralogically characterized. Their potential pozzolanic character was assessed by mean of R³ tests with a follow up of the evolution of hydrates suite (consumption and precipitation), doubled with mechanical strength on mortar for different formulated binders, combining materials to simulate standardized cement types according to European standards EN197-1 and -5. The overall results indicate their reactivity were good enough to conclude that these materials can be considered as potential alternative SCMs.