• Advances in concrete construction
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• v.11 no.3
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• pp.219-229
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• 2021

In recent years, geopolymer cements, have gained significant attention as an environmental-friendly type of cement. In this experimental research, effects of different alkaline activator solutions and variations of associated parameters, including time of addition, concentration, and weight ratio, on the mechanical strengths of Granulated Ground Blast Furnace Slag (GGBFS)-based Geopolymer Concrete (GPC) were investigated. Investigation of the effects of simultaneous usage of KOH and NaOH solutions on the tensile and flexural strengths of GGBFS-based GPC, and the influence of NaOH solution addition time delay on the mechanical strengths is among the novel aspects investigated in this research. four series of mix designs and corresponding specimen testing is conducted to study different parameters of the active alkali solutions on GPC mechanical strengths. The results showed that addition of NaOH to the mix after 3 min of mixing KOH and Na2SiO3 with dry components (1/3 of the total mixing duration) resulted in the highest compressive, tensile and flexural strengths amongst other cases. Moreover, increasing the KOH concentration up to 12 M resulted in the highest compressive strength, while weight ratio of 1.5 for Na2SiO3/KOH was the optimum value to achieve highest compressive strengths.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.39-40
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• 2016

The aim of this research was evaluating strength characteristics of foamed concrete using Ladle Furnace slag with GGBFs. For all mixtures, because of the early setting and strength development, it was possible to deform the formwork and measure the compressive strength within 3 hours.

• Journal of the Korea Institute of Building Construction
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• v.12 no.4
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• pp.393-400
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• 2012

The effect of ground granulated blast-furnace slag (GGBS) and alkaline activator on the properties of setting, compressive strength, drying shrinkage and resistance of carbonation was assessed to develop high volume slag concrete, the GGBS replacement rate of which was more than 80 percent. The changes in the concrete as the replacement rate of GGBS increases were as follows. Initial and final setting time was delayed by two and a half hours, and the compressive strength development properties of concrete in early and long term age were decreased. Drying shrinkage was satisfactory as below $6{\times}10^{-4}$ in every mixture, and yet showed a tangible trend by replacement rate. Carbonation was materially increased. Setting time and early strength development property, however, were extremely advanced by the addition of the alkaline activator. While drying shrinkage was improved by the alkaline activator, resistance to carbonation was not.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.315-320
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• 2002

The effects of slag content and polymer-binder ratio on the strength properties of the polymer-modified concretes using ground granulated blast-furnace slag and a styrene-butadiene rubber (SBR) latex are examined. As a result, the compressive, tensile and flexural strengths of the SBR-modified concretes using slag increase with increasing polymer-binder ratio and slag content, and maximized at a slag content of 40 ％. In particular, the SBR-modified concretes with a slag content of 40 ％ provide approximately two times higher tensile and flexural strengths than unmodified concretes. Such high strength development is attributed to the high tensile strength of SBR polymer and the improved bond between cement hydrates and aggregates because of the addition of SBR latex.

• Computers and Concrete
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• v.20 no.1
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• pp.77-84
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• 2017

Shirasu, a pyroclastic flow deposit, showed considerable performance as aluminosilicate source in geopolymer, based on past research. However, the polymerization reactivity was somewhat lower compared to the traditional fly ash based geopolymer even though the long-term strength was fairly good. The present study concentrates on the development of higher initial strength performance of Shirasu based geopolymer by utilizing ground granulated blast furnace slag as an admixture. Mortars with various mix proportions were adopted to study the effect of parametric changes on strength development along with the addition of slag in different percentages. A combination of sodium hydroxide and sodium silicate was used as alkaline activators considering parameters like molar ratios of alkali to geopolymer water and silica to alkali molar ratio. The mortars were cured at elevated temperatures under different curing conditions to analyze the effect on strength development. Compressive strength test, mercury intrusion porosimetry and X-ray powder diffraction were carried out to assess the strength performance and microstructure of slag-Shirasu based geopolymer. Based on the experimental study, it was observed that the initial and long-term strength development of Slag-Shirasu geopolymer were improved by the addition of slag.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.72-77
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• 1995

Blast-furnace slag cement has been used widely as a structural material due to the latent hydraulicity of granulated ground blast furnace slag(GGBS)for a long time as The wall as ordinary portland cement. In this study, based on the fundamental investigation on the high strength and high durable concrete using the high fineness GGBS the following remarks can be made. 1) The average desired strenth of concrete is Or=600~800kg/$\textrm{cm}^2$. 2) The above high strength concrete using the high fineness GGBS is more workable than those using only OPC. 3) The adiabatic temperature and drying shringkage decrease, so the density and resistance to sea water attack increase as results. 4)The unit cement content and unit air entrained admixture at the same desired strength of concrete decrease, so the economical high strength concrete can be manufactured from using the high fineness GGBS.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.569-572
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• 2006

This study was performed to investigate the characteristics of carbonation for latex modified concrete with fly ash and blast furnace slag. The experimental variables consisted of ground granulated blast-furnace slag contents (0%, 30%, 50%), fly ash contents (0, 30%) latex contents (0, 5, 10, 15%). Two different methods of carbonation test such as $CO_2$ gas and 5% sulphuric acid digestion resistance test were varied in this study.

• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.195-204
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• 1998

Generally, in order to maintain high strength in concrete, it needs high cement content and low water-cement ratio.makes internal temperature rising after concrete placing inevitably, and happens temperature stress that makes initial cracks of concrete structure. Therefore, to control the thermal stress of high-strength concrete, we made 3 types of the fineness of ground granulated blast-furnace slag and 4 steps replacement. and then measured an amount of temperature rising and elapsed time of maximum temperature and strength of concrete. Also we considered the test results of heat evolution amount and heat evolution of cement paste made with 5 steps replacement by GGBF slag.As result of this study, in case of the 50% of replacement and the 6,000$\textrm{cm}^2$/g of fineness, we obtained satisfactory results that not only the controlled effect of temperature rising but strength at early ages.

• Journal of the Korean GEO-environmental Society
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• v.23 no.11
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• pp.5-11
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• 2022

The objective of this study is to evaluate the mechanical properties of high-flowable retaining wall material (RWM) incorporated with ground granulated blast-furnace slag (SG) and steel fiber (SF) based on a comparison with those of ordinary portland cement (OPC). To produce the specimens of RWM, some chemical agents such as superplasticizer (SP), air-entrained agent (AEA) and viscosity modifying agent (VMA) are added in the fresh RWM. The compressive, split tensile and flexural strength measurements were performed on the hardened RWM specimens. Additionally, surface electric resistivity and absorption tests according to ASTM standards were carried out at predetermined periods after water curing. It was found that the mechanical properties of slag cement concrete (SGC) RWM mix are better than those ordinary portland cement concrete (OPC) RWM mix. The effect of SF is remarkable to improve the mechanical properties of RWM mixes. It is noted that the usage of SG shows a beneficial effect to resist water penetration as well as long-term strength development of RWM mixes.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.23-26
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• 2002

Ternary blended concrete containing both fly ash and granulated blast furnace slag is initial cost effective, and environment friendly. Furthermore, it has many technical advantages such as improvement of long term compressive strength, rheology property, reduction of hydration heat, etc. However, use and data on the performance of ternary blended concrete are limited, and it is necessary to study on the adoption of this technology. This study examined the durability performance of ternary blended concrete comparing with binary blended concrete and ordinary portland concrete. From the results of this study, it was concluded that ternary blended concrete is very suitable to submerged zone under maine environment.