Influence of different calcined clays on the water transport performance of concretes

Abstract

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.

Suitability of Clinker Replacement by a Calcined Common Clay in Self-Consolidating Mortar—Impact on Rheology and Early Age Properties

“…The volume fraction of the gel pores in the systems with CC was greater than the reference, whereas the fraction of capillary pores was smaller. This pore size refinement was related to the pozzolanic reaction and the formation of more AFm phases in the binder systems with CC, as observed, e.g., by [17,[68][69][70][71]. Figure 13 shows the specific pore volume of SC-P produced with and without CC as measured by MIP at 28 days of hydration.…”

Uso de arcillas argentinas naturales y calcinadas para la remoción de Cd(II) de soluciones acuosas

“…Considerando que en la región de la UNCPBA, se cuenta con illita calcinada producida industrialmente para su uso como material cementíceo suplementario (Tironi et al, 2022), resulta de interés estudiar cómo se ve afectada la capacidad de adsorción de las arcillas cuando se las trata térmicamente. El objetivo del presente trabajo es evaluar los cambios en la adsorción de Cd(II), cuando se utilizan arcillas de mediano contenido de mineral arcilloso, naturales y calcinadas.…”

Disposición final de arcillas calcinadas con Cd(II) adsorbido en matrices calcáreas: evaluación del crecimiento fúngico

“…Para la elaboración de las pastas se utilizó cal hidráulica (CalH) y arcillas calcinadas con y sin Cd adsorbido: arcilla illítica calcinada con Cd adsorbido (IC-Cd, 14 mg Cd(II) / g IC); arcilla illítica calcinada con actividad puzolánica lenta (IC) (Tironi et al, 2022b); arcilla caolinítica calcinada con Cd adsorbido (CDC-Cd, 3 mg Cd(II) / g CDC); y arcilla caolinítica calcinada con elevado contenido de aluminio y mayor reactividad puzolánica (CDC) (Tironi et al, 2022b). En la Tabla 1 se presenta la composición química de las arcillas calcinadas y de la cal hidráulica.…”

“…En la Tabla 1 se presenta la composición química de las arcillas calcinadas y de la cal hidráulica. La arcilla illítica fue producida en forma industrial a 950 °C y la arcilla caolinítica fue calcinada a 700 °C durante 30 minutos en mufla (Indef modelo 272) (Tironi et al, 2022b).…”