• 한국세라믹학회지
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• 제37권5호
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• pp.453-458
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• 2000

Glasses showing the composition of blast furnace slag were made in the laboratory, and the effect of the chemical composition on the latent hydraulic activity of the slags was examined. The latent hydraulicity was greatly influenced by the composition change, the optimal characteristic of the hydraulicity was achieved at the slag composition of 47CaO:20Al2O3:33SiO2. The content of CaO and Al2O3 were not equivalent to the hydraulic activity of the slags as the b-formula (KS L 5210) indicates. Good latent hydraulicity was shown when Al2O3 was richly contained at the high (CaO＋Al2O3):SiO ratio, while the more the MgO content was, the more negative the result turned out.

• Advances in concrete construction
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• 제6권2호
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• pp.103-121
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• 2018

This paper reports the effects of coarse and fine recycled concrete aggregates (RCA) on fresh and hardened properties of self-compacting concrete (SCC) containing ground granulated blast-furnace slag (GGBFS) as cement replacement. For this purpose, three SCC mixes groups, were produced at a constant water to binder ratio of 0.38. Both fine and coarse recycled aggregates were used as natural aggregates (NA) replacement at different substitution levels of 0%, 25%, 50%, 75% and 100% by volume for each mix group. Each group, included 0, 15% or 30% GGBFS as Portland cement replacement by weight. The SCC properties investigated were self-compactability parameters (i.e., slump flow, T500 time, V-funnel flow time, L-box passing ability and sieve stability), compressive strength, capillary water absorption and water penetration depth. The results show that the combined use of RCA with GGBFS had a significant effect on fresh and hardened SCC mixes. The addition of both fine and coarse recycled aggregates as a substitution up to 50% of natural aggregates enhance the workability of SCC mixes, whereas the addition from 50 to 100% decreases the workability, whatever the slag content used as cement replacement. An enhancement of workability of SCC mixes with recycled aggregates was noticed as increasing GGBFS from 0 to 30%. RCA content of 25% to 50% as NA replacement and cement replacement of 15% GGBFS seems to be the optimum level to produce satisfactory SCC without any bleeding or segregation. Furthermore, the addition of slag to recycled concrete aggregates of SCC mixes reduces strength losses at the long term (56 and 90 days). However, a decrease in the capillary water absorption and water permeability depth was noticed, when using RCA mixes with slag.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.177-180
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• 2004

In these days the exhaustion of natural sand has been highlighted with the environmental damages due to excavating sea-sand. Many researchers and engineers have investigated some materials to replace natural sand with, and were interested in using the basic oxygen furnace-slag, the industrial by-product, as fine aggregate. One of the drawbacks to using BOF-slag as a aggregate is to be gradually expanded, and needed the time-consuming process, but some engineers in Korea tackled it recently. In this study, the stabilized BOF-slag was used for lean concrete under the laboratory condition. After testing the several properties - dry density, compressive strength, and young's modulus-, it was found that the dry density was proportionally governed by BOF-slag content and the 7-day compressive-strength was $110\~120\%$ of the natural sand-made. Therefore, BOF-slag is applicable to the lean concrete because they greatly satisfied the required strength, $50kgf/cm^2$.

• Geomechanics and Engineering
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• 제10권2호
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• pp.247-256
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• 2016

In this paper, based on understanding the design theories on soil stabilization, a series of soil stabilizers were prepared with different kinds of industrial wastes such as calcined coal gangue (CCG), blast furnace slag (SS), steel slag (SL), carbide slag (CS), waste alkali liquor (JY), and phosphogypsum (PG). The results indicated that when the Portland cement (PC) proportion was lower than 20% in the stabilizer, for the soil sample selected from Wuhan (WT) and Beijing (BT), the unconfined compress strength (UCS) of the stabilized soil specimens could increase 4.8 times and 5.4 times respectively than that of the specimens stabilized only by PC; compared with the UCS of the specimen stabilized only by PC, the UCS of the specimen which was made from soil sample WT and stabilized by the stabilizer composed only by CCG, CS, and PG increased 1.5 times, and UCS of the specimen which was made from soil sample BT and stabilized by the stabilizer composed only by SS, JY, and PG increased 4.5 times.

• 기술사
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• 제33권4호
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• pp.77-83
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• 2000

In this study, engineering characteristics of permeable mortar using water-quenched blast furnace slag as fine aggregates were analyzed by laboratory experiments to examine its suitability for permeable concrete pavement techniques. Engineering characteristics of mortar were investigated by performing both the compressive, flexural strength tests together with the constant head permeability tests for twenty-six types of mixing samples having different percetage of slag, cement and water. After 28days of curing, every performance was tested to find optimum mixture. When the go coefficient of permeability was 10$\^$-2/cm / sec and flexural strength was 30kg/㎠, we conclusion that the best mix design in permeable mortar was made in the condition,60% of cement and 20% of water percentage of unit slag contents. From the present investigations, it is concluded that suitability for permeable concrete pavement techniques using water-quenched blast furnace slag as fine aggregates may possibly be used to achieve effects on strength together with drainage effects.

• Computers and Concrete
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• 제6권1호
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• pp.19-40
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• 2009

This paper describes the development of modified heat of hydration and maturity-strength models for concrete containing fly ash and slag. The modified models are developed based on laboratory and literature test results, which include different types of cement, fly ash, and slag. The new models consider cement type, water-to-cementitious material ratio (w/cm), mineral admixture, air content, and curing conditions. The results show that the modified models well predict heat evolution and compressive strength development of concrete made with different cementitious materials. Using the newly developed models, the sensitivity analysis was also performed to study the effect of each parameter on the hydration and strength development. The results illustrate that comparing with other parameters studied, w/cm, air content, fly ash, and slag replacement level have more significantly influence on concrete strength at both early and later age.

• Geomechanics and Engineering
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• 제3권3호
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• pp.207-218
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• 2011

This article describes laboratory research done on strength evaluations for stabilized samples made of tropical fibrous peat. The stabilizing agents used were ordinary Portland cement (OPC) as binding agent and blast furnace slag (BFS) as additive. Stabilized samples were tested for their strength through unconfined compressive strength (UCS) and California bearing ratio (CBR). Different dosage rates of OPC and BFS were used in trial and error experiments for the most effective combination for stabilized peat samples that were at their natural moisture content. Stabilized trial samples were air cured for 90 days. After detecting the most effective dosage rate in the trial samples, their values were used to prepare CBR samples at their optimum moisture content (OMC). CBR samples were then air cured from 1 to 90 days and tested under un-soaked and soaked conditions. The most effective dosage rate for the stabilized peat samples was found to be close to when 75% for OPC and 25% of BFS per total weight of OPC, and BFS. As an example, if 11.25% OPC, and 3.75% BFS are mixed with peat and compacted at their OMC and air cured for 90 days, stabilized peat will have an increase in CBR of 0.8% to 45 % for un-soaked and 20% for soaked conditions.

• Computers and Concrete
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• 제34권4호
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• pp.489-501
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• 2024

Geopolymers are part of a class of materials characterized by properties combining polymers, ceramics, and cement. These include exceptionally high thermal and chemical stability, excellent mechanical strength and durability in aggressive environments. This work deals with the synthesis, characterization, and sustainability evaluation of GP_GBFS-MK geopolymers by alkaline activation of a granulated blast furnace slag-metakaolin mixture. In the first step, elemental and oxide analyses by XRF and EDS showed that the main constituents of GP_GBFS-MK geopolymers are silicon, sodium, and aluminium oxides. The structural analyses by XRD and FTIR confirmed that the geopolymerization for GP_GBFS-MK geopolymers did occur, accompanied by the formation of disordered networks from the blends and a modification to the microstructure by the geopolymerization process. Similarly, the microstructural study made by SEM showed that the GP_GBFS-MK geopolymers are constituted by aluminosilicates in the form of dense clusters on which are adsorbed particles of unreacted GBFS in the form of spheroids and white residues of the alkaline activating solution. In addition, the study of the sustainability evaluation of GP_GBFS-MK geopolymers showed that the water absorption of geopolymeric materials is lower than that of OPC cement. As for the elevated temperature resistance, the analyses indicated an excellent elevated temperature resistance of GP_GBFS-MK. In the same way, the study of the resistance to chemical aggressions showed that the GP_GBFS-MK geopolymeric materials are unattackable, contrary to the OPC cement-based materials which are strongly altered.

• Advances in concrete construction
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• 제11권3호
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• pp.231-238
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• 2021

The present work aims at investigating the effects of using various fine mineral additions as partial replacement to Portland cement on the tribological properties of concrete. To achieve this goal, concrete mixtures were prepared with different percentages (10, 20 and 30%) of limestone fillers (LF) and natural pozzolana (NP), and (20, 40 and 60%) of blast furnace slag (BFS). The interface yield stress (τ0) and viscous constants (η) that allow characterizing friction at the concrete-pipe wall interface were determined using a rotational tribometer. In addition, the compositions of the boundary layers that formed in the pumping pipes of the different concretes under study were also identified and analyzed. The experimental results obtained showed that the concretes studied have a linear tribological behavior that can be described by the Bingham model. Furthermore, the use of different mineral additions, especially limestone fillers and blast furnace slags, even at high rates, had a beneficial effect on the optimization of the volume of paste present in the boundary layer, which made it possible to significantly reduce the viscous constant of concrete. However, a maximum rate of 10% of natural pozzolana was recommended to achieve tribological properties that are favorable to the pumpability of concrete.

• 한국지반환경공학회 논문집
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• 제17권12호
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• pp.45-54
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• 2016

본 연구에서는 벤토나이트로 굴착 트렌치의 안정성을 유지하면서 시멘트와 벤토나이트 혼합물을 불투수벽체의 재료로 사용하여 지중차수벽체를 구성하는 새로운 시공방법에 대해 고찰하였다. 강화벤토나이트 차수벽체공법은 굴착된 구역을 균질하게 차수재료로 치환하므로 일반적인 그라우팅공법에 비해 차수효과의 예측과 시공성과의 검증이 보다 용이한 장점을 지닌다. 또한 강화벤토나이트 차수벽체공법은 시공 장비가 단순하고 시공 순서가 간단하므로 경제적인 측면에서도 큰 장점을 가지고 있다. 본 연구에서는 다양한 실내실험을 통해 배합재료와 배합방법의 변화에 따른 강화벤토나이트 차수벽체의 공학적 특성을 고찰하였으며, 본 공법의 실무 적용 시 시공비용 결정과 벽체의 설계를 위해 가장 중요한 표준 배합비와 배합방법을 제시하였다. 마지막으로 차수벽체를 구성하는 재료들의 결합재로 사용되는 일반포틀랜드 시멘트와 고로슬레그 시멘트의 효과를 비교하였다.