Utilization of Some Egyptian Waste Kaolinitic Sand as Grog for Bricks and Concrete

The aim of the present study is to assess the suitability of some waste kaolinitic sand as grog for bricks and concretes. Three samples were selected and their chemical and mineralogical compositions as well as their ceramic and mechanical properties were investigated. The solid phase composition as well as the microstructure of the vitrified samples was also carried out using XRD and SEM methods. Refractoriness under load and thermal shock resistance are also investigated. Chemical and phase composition confirm that two samples (1 and 2) are fireclay with total impurities oxide contents (TIOC) less than 3.0 % while the third is mainly silica with TIOC less than 0.5 %. The microstructure of samples 1 and 2 shows predominant mullite crystals, bonded by silicate phases as confirmed by XRD, whereas silica phases are the main components of the third sample with minor intercalation of mullite phase. It is concluded that samples 1 and 2 fired at 1500 ?C can be used as grog for brick and concrete manufacture in industrial furnaces up to 1400 °C while sample 3 needs some additives to form denser grains.