The environmental aspects involved in the production and use of cement, concrete and other building materials are of growing importance. CO2 emissions are 0.8-1.3 ton/ton of cement production in dry process. SO2 emission is also very high, but is dependent upon the type of fuel used. Energy consumption is also very high at 100-150 KWT/ton of cement produced. It is costly to erect new cement plants. Substitution of waste materials will conserve dwindling resources, and will avoid the environmental and ecological damages caused by quarrying and exploitation of the raw materials for making cement. To some extent, it will help to solve the problem otherwise encountered in disposing of the wastes. Partial replacement of clinker or portland cement by slag, fly ash, silica fume and natural rock minerals illustrates these aspects. Partial replacement by natural materials that require little or no processing, such as pozzolans, calcined clays, etc., saves energy and decreases emission of gases. The output of waste materials suitable as cement replacement (slags, fly ashes, silica fumes, rice husk ash, etc.) is more than double that of cement production.
These waste materials can partly be used, or processed, to produce materials suitable as aggregates or fillers in concrete. These can also be used as clinker raw materials, or processed into cementing systems. New grinding and mixing technology will make the use of these secondary materials simpler. Developments in chemical admixtures: superplasticizers, air entraining agents, etc., help in controlling production techniques and, in achieving the desired properties in concrete.
Use of waste products is not only a partial solution to environmental and ecological problems; it significantly improves the microstructure, and consequently the durability properties of concrete, which are difficult to achieve by the use of pure portland cement. The aim is not only to make the cemen
Engineers, scientists in concrete manufacturing.
- Properties and Use of Solid Residue From Fluidized Bed Coal Combustion Introduction Starting Materials and the Combustion Process The Chemical and Phase Composition of AFBC and PFBC Ashes The Reactivity of Fluidized Bed Ashes The Analysis of Ashes and Testing of Ash Mixes Utilization of Ashes Without Additives Portland Fly Ash Cements and Composite Cements Possible Use of AFBC and PFBC Solid Residue as Constituents of Concrete Mixes The Use of Fluidized Bed Ashes in Multi-Component Portland Clinker Free Cements Autoclaved Products Artificial Concrete Aggregate Fluidized Bed Ashes as Constituents of Portland Cement Clinker Raw Meal Legal and Standardization Aspects, Performance Requirements Conclusions and Recommendations for Future Research References
- Production and Use of By-Product Gypsum in the Construction Industry Introduction Chemical Gypsums Flue Gas Desulphurization Products References
- Fly Ash In Concrete Introduction Fly Ash Characterization Effect of Fly Ash on Fresh and Hardened Concrete Properties Durability Others References
- The Use of Rice Husk Ash in Concrete Introduction Classification of Rice Husk Ash Analysis of The Quality of RHA Hydration Mechanisms of Paste with RHA Early Characteristics of Concrete with RHA The Durability Properties of Concrete with RHA Summary References
- Blast Furnace Slag - The Ultimate Binder Introduction Granulated Blast Furnace Slag<BR id="CR
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- © William Andrew 1996
- 31st December 1996
- William Andrew
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