Evaluación de arcillas multicomponentes cubanas como fuente de materia prima para la producción de materiales cementicios suplementarios
Fecha
2014-06-30
Autores
Nazco Vives, Kety
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Editor
Universidad Central "Marta Abreu" de las Villas
Resumen
En el presente trabajo se muestran los resultados obtenidos para la evaluación de la influencia de
las características químicas y mineralógicas de las arcillas de los yacimientos Pontezuela, Cayo
Guam y Castaño en la reactividad puzolánica de sus productos de calcinación. Las materias primas
fueron caracterizadas mediante DRX, FRX, FTIR y ATG. La calcinación se realizó a temperaturas
de 750˚C y 850˚C. La evaluación de la reactividad puzolánica se realizó mediante ensayos de
Calorimetría Isotérmica en pastas y resistencia mecánica en morteros con un 30% de sustitución de
CPO por arcillas calcinadas. La arcilla de Cayo Guam (58% de caolinita) mostró la mayor
reactividad puzolánica, con valores de resistencia mecánica superiores a los de la serie control
(100% CPO) a todas las edades, mientras que para la arcilla de Pontezuela (45.7% de caolinita y
38.7% de arcillas tipo 2:1) los valores de resistencia mecánica son similares o inferiores a los de la
serie control. En ambos casos se observa un incremento en la velocidad de hidratación de los
silicatos y un intenso efecto asociado al contenido de alúmina reactiva. Para el material arcilloso de
Castaño (40% de montmorillonita y 23% de calcita), se alcanzan valores de resistencia a la
compresión similares a los de la serie control a los 7 y 28 días, para una temperatura de
calcinación de 750°C, parcialmente asociado a la formación de fases con carácter hidráulico
durante su activación térmica. Las pastas con incorporación de este material presentan un
comportamiento similar al del CPO y valores de calor total acumulado superiores a los de la serie
filler.
In this work, the results for the assessment of the influence of the chemical and mineralogical characteristics of the raw materials from the clay deposits of Pontezuela, Cayo Guam and Castaño in the pozzolanic reactivity of its calcination products are presented. The raw materials were characterized by XRD, XRF, FTIR and TGA. Thermal activation was carried out at 750°C and 850°C. The assessment of the pozzolanic reactivity of the calcination products was carried out through essays of Isothermal Calorimetry in pastes and compressive strength in mortars with a 30% replacement of OPC by calcined clays. The clayey material from Cayo Guam (58% of kaolinite) shows the highest pozzolanic reactivity, with values of compressive strength higher than the control series (100% OPC) at all ages, whereas for the clay from Pontezuela (45.7% kaolinite and 38.7% 2:1 clays) values of compressive strength are similar or lower than for the control series. An increase in the reaction rate of calcium silicates and an intense exoth ermic effect associated to the hydration of alumina rich phases is observed for both materials. For clayey material from Castaño (40% montmorillonite and 23% calcite), values of compressive strength are similar to the control series at 7 and 28 days, for a calcination temperature of 750°C. This behavior is partially associated with the formation of phases with hydraulic properties during the process of thermal activation. The pastes prepared with this material exhibits a behavior similar to the OPC, but with values of cumulated heat per gram of OPC higher than the filler.
In this work, the results for the assessment of the influence of the chemical and mineralogical characteristics of the raw materials from the clay deposits of Pontezuela, Cayo Guam and Castaño in the pozzolanic reactivity of its calcination products are presented. The raw materials were characterized by XRD, XRF, FTIR and TGA. Thermal activation was carried out at 750°C and 850°C. The assessment of the pozzolanic reactivity of the calcination products was carried out through essays of Isothermal Calorimetry in pastes and compressive strength in mortars with a 30% replacement of OPC by calcined clays. The clayey material from Cayo Guam (58% of kaolinite) shows the highest pozzolanic reactivity, with values of compressive strength higher than the control series (100% OPC) at all ages, whereas for the clay from Pontezuela (45.7% kaolinite and 38.7% 2:1 clays) values of compressive strength are similar or lower than for the control series. An increase in the reaction rate of calcium silicates and an intense exoth ermic effect associated to the hydration of alumina rich phases is observed for both materials. For clayey material from Castaño (40% montmorillonite and 23% calcite), values of compressive strength are similar to the control series at 7 and 28 days, for a calcination temperature of 750°C. This behavior is partially associated with the formation of phases with hydraulic properties during the process of thermal activation. The pastes prepared with this material exhibits a behavior similar to the OPC, but with values of cumulated heat per gram of OPC higher than the filler.
Descripción
Palabras clave
Arcillas Multicomponentes Cubanas, Materia Prima, Materiales Cementicios Suplementarios, Arcilla de Cayo Guam, Arcilla de Pontezuela, Clay