Ceramics-Silikáty 59, (2) 81 - 89 (2015) |
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CHARACTERISTICS AND DURABILITY OF ALKALI ACTIVATED SLAG-MICROSILICA PASTES SUBJECTED TO SULPHATE AND CHLORIDE IONS ATTACK
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Heikal Mohamed 1,2, Ibrahim Sahar M. 1
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1 Chemistry Department, Faculty of Science, Benha University, Benha, Egypt
2 Chemistry Department, College of Science, Al Imam Mohammad Ibn Saud Islamic University (IMSIU),P.O Box 90950 Riyadh 11623, Saudi Arabia
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Keywords: Alkaline activation, Mechanical properties, Electrical conductivity, Thermogravimetric analysis (TGA), Electron microscopy (SEM)
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This research aims to produce cementless eco-friendly binding material using alkaline activation of blast-furnace slag (GBFS) and microsilica (MS). The preparation of cementless binding material was conducted with different GBFS-MS mass ratios (100:0; 98:2; 96:4; 92:8) with 0.75:0.50; Na₂O:SiO₂ mol kg⁻¹ of GBFS-MS. The characteristics and durability of alkali activated GBFS and MS mixes were studied. Chemically combined water, combined slag contents as well as compressive strength increase with MS up to 4 mass %, then decreases with MS up to 8 mass %. Increase of MS content up to 8 mass %, the compressive strength shows a lower values at early ages (3-14 days). But, at later age up to 28-90 days, the compressive strength values increase. SEM micrographs show the presence of C-S-H and (N,C)-A-S-H gel with low porosity. The alkali activated GBFS-MS pastes are more durable in 5 % MgSO₄ or 5 % MgCl₂ solution than ordinary Portland cement (OPC) up to 180 days. |
Record in: Scopus | Web of Science |
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