EVALUATION OF AL-KEND HILLIS CLAY FOR PRODUCTION OF FACING BRICKS AND FLOORING TILES

Abstract

Investigation was carried out to prepare facing bricks and flooring tiles by using Al-Kend hills clays in Naenava governorate due to the characteristics variation, clay and non-clay contents. The optimum conditions for the production were also identified according to characteristics of Al-Kend clay. The effect of firing temperatures 1050, 1075, 1100, 1125, and 1150 ˚C on the physical, mechanical properties and durability were studied according to certain firing program (5˚C/min, soaking time one hour)for four clay samples from different locations of Al-Kend area. Clay samples were prepared by drying, crushing, sieving at 1 mm, wetting (water percentage 12-18%), left 3 days for moisture homogeneity, and formed by extrusion, facing brick and tiles dimensions were (7.24*3.05*2.47)cm and (7.2*2.35*0.75)cm respectively. The formed bricks and tiles were dried at room temperature for 48 hr and for 24 hr at 100 ˚C using laboratory oven, and fired in muffle furnace. The results have shown that clay characteristics affected on the suitable firing temperature, sample which has high sand content (K7S22), high firing temperature should be used to reach firing maturity, and for sample has high clay content (montmorillonite, palygorskite minerals) and fluxes materials (K3S4) , the firing maturity was reached at low firing temperature (1075 ˚C). To improve some failed bricks and tiles (white spots on the external surface): a- Sample K7S22 were submerged in water for 2 hours (slaking). b-Unfired bricks and tiles of Sample K7S2 were covered with raw clay (K3S4) which has low melting temperature to protect the external surface from the weathering effects by making matt glaze appearance, this process also provide a further consumption for the raw clay (K3S4).