New additions for eco-efficient cement design. Impact on calorimetric behaviour and comparison of test methods

The pursuit of new alternative construction materials has intensified substantially in recent years due to the economic, technical and environmental benefits deriving from their use. The study of the effect of such materials on heat of hydration is of particular importance, for any rise in that parameter may shorten the service life of concrete structures considerably. This paper describes an in-depth study of including clay-based sanitary ware (SW) and construction and demolition (CDW) waste as active additions in clinker manufacture and their effect on the total heat of hydration measured with isothermal and semi-adiabatic calorimetry. Clay-based SW waste induced a greater decline in the heat production rate, temperature rise and total heat than CDW waste. Moreover, the downslopes steepened with increasing replacement ratios. A linear relationship was observed between the values for total heat of hydration found with the two test methods. The type of waste, replacement ratio and the interaction between these two parameters had a significant impact on heat of hydration.