Browsing by Author "Youssof, IM"

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    Characterization of waste-glass as mortar fine aggregate
    (BELGIAN CERAMIC SOCIETY, 2004) Shoaib, MM; Youssof, IM
    Waste glass is one of the most solid pollutants from industrial and civilian uses, which are contaminated by some hazard substances. So, it is very important to reuse these wastes for reducing the pollution created from accumulation of several tons of these materials. The utilization of soda lime silica glass which is the most commercially glass used as fine aggregate in some blended cement mortars was studied. Different percentages of glass grains with similar grain sizes were used instead of sand in preparation of mortars made from ordinary portland cement. The characteristics of prepared mortars and cement glass bond were investigated by determination of compressive strength and bulk density. The hydration kinetics of cement mortars was evaluated by determination of free lime and chemically combined water contents as well as the change of pH values of hydration media. The results show that the bulk density and the compressive strength values gradually decrease with increasing of glass substituted content and polyvinyl alcohol (PVA) used. The chemically combined water as well as free lime contents shows that there is some of pozzolanic activity of glass as alkali-activated aggregate to be used in some selected mortars as a base for lightweight concrete.
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    Ultrasonic and structural studies on TiO2-doped CaO-Al2O3-B2O3 glasses
    (WILEY-V C H VERLAG GMBH, 2003) Abd El-Moneim, A; Abd El-Daiem, AM; Youssof, IM
    TiO2-doped 30CaO-30Al(2)O(3)-40B(2)O(3) glasses have been prepared by the melt quenching method over a wide range of composition (TiO2 = 5, 10, 15, and 20 mol%). The longitudinal velocity and attenuation of ultrasonic waves were measured in these glasses at room temperature using the pulse-echo technique. The acoustic impedance and longitudinal modulus were calculated and are discussed quantitatively in terms of the structural parameters, such as packing density, dissociation energy per unit volume, field strength of the modifiers, number of network bonds per unit volume, average cross-link density and the number of two-well systems (loss centers) per unit volume of the glass. The composition dependence of these parameters suggested that Al2O3 associates itself with CaO to form AlO4 tetrahedra and Ti4+ ions are incorporated in the network as TiO6 octahedra. This leads to an increase in the three-dimensional linkage and rigidity of the network. Moreover, the theoretical elastic moduli were calculated for these glasses from the chemical composition and the experimentally determined density using the Makishima and Mackenzie model. Results showed that the model is valid for the studied glasses. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.