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Title |
Mechanical Properties of Granulated Ground Blast Furnace Slag on Blended Activator of Sulfate and Alkali
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Authors |
김태완(Tae-Wan Kim) ; 전유빈(Yu-Bin Jun) ; 엄장섭(Jang-Sub Eom) |
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DOI |
http://dx.doi.org/10.11112/jksmi.2015.19.5.104 |
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Keywords |
황산칼슘 ; 황산나트륨 ; 수산화나트륨 ; 혼합 활성화제 ; 알칼리 활성화 슬래그 시멘트 Calcium sulfate ; Sodium sulfate ; Sodium hydroxide ; Blended activator ; Alkali-activated slag cement |
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Abstract |
This study shows the mechanical properties of alkali-activated slag cement (AASC) synthesized using sulfate with NaOH solution. The used sulfates were calcium sulfate (CaSO4, denoted CS) and sodium sulfate (Na2SO4, denoted SS). The replacement ratio of sulfates was 2.5, 5.0, 7.5 and 10.0% by weight of slag. NaOH solution of 2M and 4M concentration was used. A sample was activated with sulfate and activated with blended activator (blending NaOH solution with sulfate) respectively. 24 mix ratios were used and the water-binder weight ratio for the test was set 0.5. This research carried out the compressive strength, flexural strength, ultrasonic pulse velocity (UPV), absorption and X-ray diffraction (XRD). In the case of samples with CS, sample with 7.5% CS, sample with 2M NaOH+5.0% CS and sample with 4M NaOH+5.0% CS showed the good performance in the strength development. In the case of samples with SS, sample with 10.0% SS, sample with 2M NaOH+7.5% SS and sample with 4M NaOH+2.5% SS obtained good performance in strength. The results of UPV and water absorption showed a similar tendency to the strength properties. The XRD analysis of samples indicated that the hydration products formed in samples were ettringite, CSH and silicate phases. In this study, it is indicated that when compared to the use of sulfate only, the use of both sulfate and NaOH solution makes mechanical properties of AASC better.
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