This study compares the pozzolanic activity of kaolinitic and illite clays after calcination as they are the most abundant types of clays worldwide. The impact of calcined clays on microstructure development is tested by determining the porosity of cement paste as well as by phase and optical analysis of cement matrix and interfacial transition zone of concrete. As water transportation with damaging carbonate or chloride ions is the main reason for reduced durability of reinforced concrete, the results are complemented with water absorption tests on blended concretes. At 28 days, system with calcined kaolinitic clay reveal a higher densification of its microstructure with lower water absorption rate compared to plain concrete and concrete with calcined illite clay, which is related to its higher pozzolanic reactivity. Nonetheless calcined illite clays can be considered as low-cost clinker replacement as a significant pozzolanic contribution is detectable and after 90 days, the water absorption behaviour is comparable with those of the other systems investigated.

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Demolition ceramic wastes (DCWs) were investigated in order to determine their potential use as supplementary cementitious materials in Portland Blended Cements (PBCs). For this purpose, three ceramic wastes were investigated. After characterization of the materials used, the effect of ceramic waste replacement (8, 24 and 40% by mass) was analyzed. Pozzolanic activity, hydration progress, workability and compressive strength were determined at 2, 7 and 28 days. The results showed that the ground wastes behave as filler at an early age, but as hydration progresses, the pozzolanic activity of ceramic waste contributes to the strength requirement. RESUMEN:Cementos Portland con adiciones: manejo de residuos cerámicos de demolición. Se estudiaron residuos cerámicos de demolición (DCWs) a fin de determinar su potencial uso como materiales cementicios suplementarios en cementos mezcla (PBC). Para este propósito, se investigaron tres residuos cerámicos. Luego de la caracterización de los materiales a utilizar, se analizó el efecto del reemplazo por residuos cerámico (8, 24 y 40% en peso). Se estudió la actividad puzolánica, el progreso de la hidratación, la trabajabilidad y la resistencia a compresión a 2, 7 y 28 días. Los resultados mostraron que los residuos molidos se comportaron como fillers a edades tempranas, pero con el progreso de la hidratación, la actividad puzolánica de los residuos cerámicos contribuye a los requerimientos de resistencia.