Evaluation of the Injana claystone from Central Iraq for the brick industry

Abstract

This study aims to suggest an alternative to the use of quality agricultural soil in the brick industry (Iraq). The Late Miocene claystone bed in the Injana Formation in central Iraq was targeted through the study of 18 exposed sections that were sampled by using the trench sampling method. The claystones are characterized by quartz (36.4%) followed by calcite (32.8%), quartz (36.4%) feldspar (2.6%), gypsum (1.3%) and dolomite (0.7%), kaolinite (10.5%), illite (7.7%), chlorite (6.7%), palygorskite (6.0%) and montmorillonite (0.7%). New thermal mineral phases were formed at 950°C, including diopside (62.9%), quartz (18.4%), wollastonite (8.28%), akermanite (7.6%), Anorthite (6.25%), Nosean (4.9%), gehlenite (3.75%) and Lazurite (3.15%). The raw material's engineering tests showed that the Atterberg index for the plasticity varies from low to high, low volumetric and linear shrinkage during drying and firing with a temperature at 950°C. The raw material produced bricks with 155 kg/cm2 uniaxial compressive strength, 23.2% water absorption, and zero to low efflorescence. The results show the potential use of the Late Miocene clays of the Injana Formation to replace the existing agricultural grade muds presently being manufactured within the A and B category based on the Iraqi standard specification No.25 in 1993.