• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.63-64
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• 2022

In this study, the quality of mineral admixture, Comparison of blast-furnace slag(BS) and fly ash(FA)in Korea and China. In the case of BS, Korea is mainly classified into 1 type to 4 types according to the specific surface area, whereas China is classified into S105, 95, and 75 according to the activity index of 28 days of age. In the case of FA, Korea is like BS, is mainly classified into types 1 to 4 according to specific surface area, whereas China is classified into F, C (class F, class C) by ingredients and class I, II, and III according to powder and ignition loss.

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.79-85
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• 2008

The purpose of this study is to evaluate the mix design of pH reducing cement concrete which can be used for environment-friendly concrete. Cement pastes and concretes are prepared with water-binder ratios and various admixtures such as blast-furnace slag, fly ash and recycled cement, and tested for compressive strength and pH. pH is measured through pore solution expressed from hydrated cement paste by special apparatus. From the test results, regardless of water-binder ratio, The pH of expressed pore solution from hydrated cement paste which is made of ordinary portland cement with blast-furnace slag, fly ash is decreased with increasing of admixtures content, and compressive strength is also slightly improved. The compressive strength of cement paste made of recycled cement which is burnt at $1000^{\circ}C$, for 2 hours is considerably increased compared with that of none-burnt recycled cement due to restoration of hydraulic property, but pH is a little higher. Porous concrete with ordinary portland cement has high pH in the range of 12.22 to 12.59, however, that is reduced to the range of 8.95 to 10.39 by carbonation at the surface of porous concrete. The pH reduction of porous concrete is possible by various admixture addition, however their degrees are very slight. Therefore, to reduce the pH considerably, carbonation method of porous concrete is better in pH reduction methods for plant survival condition of pH of 9.0 or less. In this study, it is apparent that pH for the environment-friendly porous concrete products used in the construction field can be suppressed by this carbonation method and various admixtures addition.

• Advances in concrete construction
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• v.6 no.4
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• pp.323-344
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• 2018

The study herein reports the impact of Steel Fiber (SF) and Ground Granulated Blast Furnaces slag (GGBFS) content on the fresh and hardened properties of fly ash (FA) based Self-Compacting Geopolymer Concrete (SCGC). Two series of self-compacting geopolymer concrete (SCGC) were formulated with a constant binder content of $450kg/m^3$ and at an alkaline-to-binder (a/b) ratio of 0.50. Fly ash (FA) was substituted with GGBFS with the replacement levels being 0%, 25%, 50%, 75%, and 100% by weight in each SCGC series. Steel fiber (SF) wasn't employed in the assembly of the initial concrete series whereas, within the second concrete series, an SF combination was achieved by a constant additional level of 1% by volume. Fresh properties of mixtures were through an experiment investigated in terms of slump flow diameter, T50 slump flow time, V-funnel flow time, and L-box height ratio. Moreover, the mechanical performance of the SCGCs was evaluated in terms of compressive strength, splitting tensile strength, and fracture toughness. Furthermore, a statistical analysis was applied in order to judge the importance of the experimental parameters, like GGBFS and SF contents. The experimental results indicated that the incorporation of SF had no vital impact on the fresh characteristics of the SCGC mixtures whereas GGBFS aggravated them. However, the incorporation of GGBFS was considerably improved the mechanical properties of SCGCs. Moreover, the incorporation of SF with the total different quantity of GGBFS replacement has considerably increased the mechanical properties of SCGCs, by close to (65%) for the splitting strength and (200%) for compressive strength.