PROPERTIES OF SOME OHIO RED‐FIRING CLAYS*

Abstract

ABSTRACTProperties of twenty‐six Ohio clays representative of those used in manufacturing heavy ware, such as brick and hollow‐ware, were studied from the raw clay to the finished laboratory product. Chemical and petrographic analyses were made. In the raw and plastic states data were obtained on the tempering water, the amount of load necessary to extrude the clay through a die, the base‐exchange capacity, and the particle‐size distribution as evidenced by sieve analysis and the water‐absorption method. In the dry state the minimum drying time, the shrinkage, porosity, apparent specific gravity, dry transverse strength, impact strength, and modulus of elasticity were determined. In the process of heating the clays to 1000°C, observations were made as to the kind and rate of evolution of the gases given off, the endothermic and exothermic reactions, and the expansion characteristics. The softening points of the clays were determined and, after heating to different temperatures, data on shrinkage, absorption, and transverse strength were taken.