Properties of cementless binders using desulfurization slag as an alkali activator
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The alkali stimulus provided by the Ca(OH)2 contained in desulfurization slag (DS), a byproduct generated in the preliminarytreatment of molten iron and composed of Ca(OH)2, CaCO3, and 2CaO·SiO2, is used to cause a cement-free binder to hardenby serving as an alkali activator for ground, granulated blast-furnace slag (BFS). The 28-day compressive strength of the BFSDSbinder was found to be about 30% that of ordinary Portland cement (OPC), but the 28-day strength of a binder madefrom BFS, DS, and anhydrous gypsum (G) was found to be similar to that of OPC. It is confirmed that BFS-DS-G bindershave very low hydration heat, which is of use in reducing the heat generated during the curing of mass concrete. The mainhydration product of the BFS-DS-G binder is found to be ettringite. Scanning electron microscope images reveal that theneedle-shaped ettringite formed in the BFS-DS-G binder is much thicker than that formed in OPC. This thick, needle-shapedettringite forms a skeletal structure, providing structural stability, and fills the gaps between hydration products such ascalcium silicate hydrates and calcium aluminum hydrates, making it highly effective in forming a dense structure. Thewidespread use of BFS-DS-G binders would result in the value-added utilization of byproducts from the iron & steel makingprocess, and provide an environmentally friendly and more economical construction material, and contribute to a reductionin CO2 emissions generated by the cement industry.
Abstract
The alkali stimulus provided by the Ca(OH)2 contained in desulfurization slag (DS), a byproduct generated in the preliminarytreatment of molten iron and composed of Ca(OH)2, CaCO3, and 2CaO·SiO2, is used to cause a cement-free binder to hardenby serving as an alkali activator for ground, granulated blast-furnace slag (BFS). The 28-day compressive strength of the BFSDSbinder was found to be about 30% that of ordinary Portland cement (OPC), but the 28-day strength of a binder madefrom BFS, DS, and anhydrous gypsum (G) was found to be similar to that of OPC. It is confirmed that BFS-DS-G bindershave very low hydration heat, which is of use in reducing the heat generated during the curing of mass concrete. The mainhydration product of the BFS-DS-G binder is found to be ettringite. Scanning electron microscope images reveal that theneedle-shaped ettringite formed in the BFS-DS-G binder is much thicker than that formed in OPC. This thick, needle-shapedettringite forms a skeletal structure, providing structural stability, and fills the gaps between hydration products such ascalcium silicate hydrates and calcium aluminum hydrates, making it highly effective in forming a dense structure. Thewidespread use of BFS-DS-G binders would result in the value-added utilization of byproducts from the iron & steel makingprocess, and provide an environmentally friendly and more economical construction material, and contribute to a reductionin CO2 emissions generated by the cement industry.
참고문헌 (31)
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