International Journal of the Physical Sciences Vol. 6(28), pp. 6596-6606, 9 November, 2011 Available online at http://www.academicjournals.org/IJPS DOI: 10.5897/IJPS11.1485 ISSN 1992 - 1950 © 2011 Academic Journals Full Length Research Paper Properties of high calcium wood ash and densified silica fume blended cement Cheah Chee Ban* and Mahyuddin Ramli School of Housing, Building and Planning, University Sains Malaysia, 11800 Penang, Malaysia. Accepted 05 October, 2011 Recycling industrial waste material as construction material to minimize production of ordinary Portland cement could solve arising industrial waste management problems and increase environmental sustainability. This study focused on the incorporation of wood biomass ash in combination with silica fume in blended cement. In this study, physical and chemical properties of high calcium wood ash (HCWA) and densified silica fume (DSF) were thoroughly characterized. Results indicated that HCWA is an active hydraulic binder material as it is rich in calcium carbonate and quicklime content. Fresh concrete properties showed HCWA-DSF blended cement pastes have marginally higher standard consistency and significantly longer setting times as compared to pure cement paste. Additionally, hard concrete properties, such as mechanical strength, water absorption, air permeability and chloride resistance properties of mortar were also investigated. Enhancement in the compressive and flexure strength of mortar was observed for mortar mixes containing DSF and HCWA. The incorporation of HCWA at level of cement replacement ranging between 4 to 12% in combination with 7.5% of DSF was observed to significantly improve the chloride resistance of mortar mixes produced. Key words: High calcium wood ash, ternary blended cement, mechanical strength, durability, recycling. INTRODUCTION The use of wood biomass as a source of renewable energy is gaining its popularity among the timber product industry and power production sector in several developed countries. Though having scarce fossil fuel resources this is especially common for countries such as Portugal and Spain. The greatest potential for long term cost savings with the use of wood biomass energy and low level emissions are the main reasons supporting the development of several full scale wood biomass power plants in these countries. This allows them to supplement the electrical energy demand of their national electrical gridlines. Moreover, the consumption of wood wastes *Corresponding author. E-mail: [email protected]. Tel: +60 0164846502. Fax: +60 046576523. Abbreviations: HCWA, high calcium wood ash; DSF, densified silica fume; XRD, X-ray diffraction pattern; XRF, X-Ray Fluorescence; ASTM, American Society of Testing Materials; LOI, loss on ignition; CP, cement paste; C-S-H, calcium silicate hydrate; OPC, ordinary Portland cement; PC, Portland cement. derived from the local logging and timber processing activities as fuel in the wood biomass power plant serves as the ultimate solution to solid waste management problems related to the aforementioned waste materials. A major problem related to electrical power production using a wood biomass power plant is the formation of significant amount of wood waste fuel ash as by-product. This normally occurs at the end of the thermal conversion process. In the absence of proper disposal technique, the fine and light weight wood ash produced poses serious air pollution and health hazards to humans. Therefore, the reuse of wood ash as a supplementary binder material in concrete is perceived as a viable and sustainable method for disposal of the waste in mass amounts without side effects to the environment. In modern civilization, structural concrete is the most common construction material with an annual con- sumption of approximately 10 billion tonnes (Yaprak et al., 2011). In conjunction with contemporary development in material science, ordinary Portland cement is widely used as the main constituent in concrete. The cement
Properties of high calcium wood ash and densified silica fume blended cement
Apr 26, 2023
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