Effect of organic binders (corchorus olitorius and abelmoschus esculentus) on the fracture behaviour of kaolin refractories
Muriuki, Njogu S.
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Both the okra and "mrenda" binders were separately prepared from vegetables by boiling in water and sieving to get the filtrate. The chemical compositions of the binders were analyzed to determine both the organic and inorganic components. The test samples for the modulus of rupture measurement were prepared using varying volume concentrations of the okra binder from 0 (plain water) to 1.0 (undiluted binder). Notched samples for the fracture toughness tests were prepared usi ng the optimum volume concentrations for plasticization for both the okra and "mrenda" binders, while the control samples were prepared using plain water. Cylindrical samples were prepared using the okra, "mrenda" and plain water for the fatigue analysis. The bulk density and apparent porosity of the samples were measured. The MOR for green and fired samples was measured using the three-point bending technique. The pre and post thermal shock elastic modulus of the samples was obtained using the ultrasonic non-destructive technique. The fracture toughness of the notched samples was measured using the three-point bend test. For fatigue analysis, samples plasticized with okra, "mrenda" and plain water were repeatedly thermal-shocked from a given temperature to room temperature until failure. The Weibull statistical approach was used to obtain the Weibull modulus and the slow crack growthparameter of the samples