A COMPREHENSIVE EVALUATION OF A NEW SOURCE OFGRANULATED BLAST FURNACE SLAG FOR USE IN CONCRETE

摘要

Cement manufacturers are currently under pressure to meet the demand for cement whileadopting Sustainable Development into their business plan. Globally, the cement industry producesapproximately 1.5 billion tonnes of cement per year and growth has been on the order of 4 percent peryear over the last decade.1 The industry contributes to approximately 3% of the world's production of CO2through the burning of fossil fuels.2 In North America there has been a reliance on imported clinker andcement to fill the gap between domestic cement production and cement demand and demand for cementis expected to increase by over 10 million tons over the next 5 years.3 Canada's signing of the Kyotoprotocol means that CO2 emissions have to be reduced to a level 6% below 1990 levels at a time whendemand for cement is going to be at record levels.4 All of this comes at a time when both Canada and theUnited States have very active Green Building movements that are being widely accepted by Architects,Engineers and Owners in both the private and the public sectors. In an effort to meet the demand forSustainable Development, the industry is fast adopting the use of supplementary cementing materials inconcrete and cement manufacturers are quickly partnering with steel companies to develop sources ofgranulated slag for use as a cementitious material after grinding.The use of slag cement as a direct mass replacement for Portland cement in concrete allows for a directreduction in the embodied CO2 by 0.9 times the percent mass replacement of slag.5 The following tableindicates the embodied CO2 in a cubic meter of concrete and potential savings in CO2 emissions.6Concrete Mix (Mpa) 15 20 30Embodied CO2 [kg/m3] 197.1 220.0 308.3With 50% Slag Cement 102.4 204 169.7Slag cement has been readily available and used in Ontario since 1972 through many large ready mixedconcrete operations but was not widely used in the Great Lakes Region of the United States. The purposeof this test program was to set the foundation for the increased utilization of Slag Cement in the UnitedStates Great Lakes Region market and bring the product to market in accelerated fashion.