Title: Calcined Clay-Based Mineral Addition for the Production of Structural Concrete
Author(s): J. Fernando Martirena, Eilys Valdes, Adrian Alujas, and Karen Scrivener
Publication: Symposium Paper
Appears on pages(s): 189-196
Keywords: calcined clay; cement; pozzolan; grinding; hydration; concrete.
This paper presents the results of the work to develop a mineral addition produced with a blend of 60% of calcined clay of kaolinitic origin, 30% of limestone and 10% of gypsum, to be added as Supplementary Cementitious Material directly while mixing concrete. The clay used has a kaolinite content within 40-50%, and has been activated at 800°C. The three components have been interground at a ball mill. The influence of the addition on cement hydration has been studied aided by Isothermal calorimetry of cement pastes having mineral additions of 35% and 50% per weight. Concrete with the minimum cement content required for the most aggressive exposure class (350 kg/m3) has been cast and mineral additions of 17% and 34% per weight have been made. Concrete strength went above 45 MPa, despite having the minimum cement content.