Characterization and utilization of calcined Turkish kaolins for improving strength and durability aspects of concrete

In this thesis, an experimental investigation on the utilization of calcined impure Turkish kaolins as supplementary cementing material to improve mechanical and durability characteristics of concrete was presented. Microstructural characteristics of the raw kaolins were analyzed and the alteration in microstructural properties were monitored as a result of calcination process. The microstructural features were measured by means of X ray diffraction analysis (XRD), thermal analyses (DTA-TG), scanning electron microscopy (SEM), particle size distribution with laser diffractometer, and Brenaur-Emmet-Teller (BET) nitrogen adsorption specific surface area measurements. Pozzolanic properties of calcined kaolins were evaluated and compared. Furthermore, commercially available high reactivity metakaolin (MK) from Czech Republic was used for comparison. The concretes of different properties including various amounts of calcined kaolins and MK were produced for comparison and evaluation of the effectiveness of the calcined kaolin on the mechanical (compressive and splitting tensile strength) and durability (gas permeability, water permeability, sorptivity, rapid chloride penetration, electrical resistivity, freezing-thawing resistance, drying shrinkage, and corrosion behavior) characteristics of concrete. Finally, an analytical study was carried out to obtain explicit mathematical formulation for estimation of the concrete properties.Keywords: Calcination, Concrete, Durability, Metakaolin, Microstructure, Strength