4937
Mohammed Abdallah Rashwan Attia
“Characterization and Evaluation of Some Ornamental Stones - Processing Wastes at Shaq El-Thoaban Area (Southern Cairo) and Their Suitability for Some Industrial Applications”
OrnamentalStones / Marble sludge / granite sludge / concretepaving products
The continuous development of ornamental stone industry in Egypt due to the increasingly great demand of the Egyptian stones, led to a continuous and increasing accumulation of huge quantities of wastes in different forms. In the area of Shaq El – Thoaban only, about 70 % of these wastes is generating. The majority of these wastes are generated in the form of sludge (semi liquid) which has a hazardous effect on the surrounding environment and the sustainable development. In the present study we used the term “marble” as a commercial name comprising the whole class of carbonate rocks amenable to sawing and polishing for decorative purposes and economically valuable. The main objective of the present study is to characterize the marble and granite sludge wastes chemically, mineralogically and physically to demonstrate their possibility as a cement substitute rather than natural aggregates in cement and concrete production besides, the suitability of using the marble sludge wastes in quicklime manufacturing. The properties of cement composites, manufactured concrete products and prepared quicklime were investigated chemically, mineralogically and physico-mechanically. Regarding cement composites pastes, the marble andgranite sludge were substituted for cement binder separately up to 40 % and combining up to 50% at certain proportions of 0% (control), 10%, 20%, 30%, 40% and 50%. The chemical, mineralogical, physical and mechanical properties of both fresh and hardened cement composites pastes including these wastes were determined at 3, 7 and 28 days curing according to standardtest methods (ASTM and/or ECP) and the results were compared with the specification requirements of these standards. Concerning the concrete mixtures, the marble sludge waste was only used as a cement replacement at certain proportions of 0%, 10%, 20%, 30% and 40% and the hardened concrete units so produced were tested for the physical and mechanical properties after 28 days curing according to standard test methods (ASTM and/or EN BS) and the results were compared with the specification requirements of these standards. With respect to quicklime, the marble sludge was fired at 1000ºC for three soaking times (15, 30 and 120 min.). The quality of prepared quicklime samples was determined in terms of available lime index and lime reactivity and the results were compared with the specification requirements of these standards. The test results showed that the addition of marble and granite sludge as cement replacement in cement composites led to an insignificant increase in water absorption and apparent porosity and decrease in compressive strength up to 20% replacement, which becomes observable at higher replacement levels compared to the control. The physical and mechanical properties of cement composites were found to conform to thestandard (ASTM and ESS).
2015
Ph.d
Ain Shams
Science