• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.257-258
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• 2010

The research was investigated the hydration heat and the fundamental properties of concrete using high volume mineral admixture for reducing hydration heat temperature. The results were that compared to OPC 100%, the dosage of superpasticizer agents was decreased about 50% degree at the same flowing, and the compressive strength was developed about 95% degree. Also, temperature rise of heat of hydration was decreased by 36~48% comparing to OPC and FA25, and it is estimated that it will have a large effect to hydration heat reduction of mass concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.67-73
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• 2011

In this study, it was investigated compressive strength generation of concrete using high volume mineral admixture obtaining fundamental data for the application of concrete structure in construction field. For this, it was evaluated compressive strength with unit binder contents($310{\sim}410kg/m^3$), replacement ratio of mineral admixture(70~90%), unit water contents($140{\sim}150kg/m^3$) and curing temperature in the normal strength range. Also, after producing mock-up structure, hydration heat and compressive strength generation was evaluated to examine properties in the concrete member. In case of concrete using a large amount of industrial byproducts which was reviewed in this study, it is possible to secure compressive strength more than 24MPa at age 28days with about $13^{\circ}C$ ambient temperature of curing condition and that is considered to be applied to structure at construction site.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.566-574
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• 2012

To address the problem of global warming, consumption of cement, the main material of concrete, should be decreased. Unfortunately, when industrial by-products are used in large quantities as admixture, the early age strength of concrete will be decreased, reducing its viability for use in concrete structures. Therefore, in this study, the application of an ionization accelerator and alkaline activator as addition agent of superplasticizer were investigated to secure a similar early age strength to that of normal concrete, thus increasing the viability of low cement concrete. Through the investigation, it was found that specimens that used a combination of Alkaline-activator (Na2Sio3) and ionization accelerator (Amine) had the highest early and long-age compressive strength. From this, we can determine an appropriate range of application of superplasticizer to improve early-age compressive strength of low cement concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.741-744
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• 2008

There are two ways to reduce cement content for a given quality level(strength, workability etc.) in concrete. First, reducing the required paste volume by varying the shape or the grading of aggregates. Secondly, holding the paste volume constant while replacing cement volume with mineral admixtures or mineral fillers. And It will also be proved that the required minimum paste volume is independent of the paste composition, provided the paste composition is in a reasonable range. In this study, therefore, we have an object to determine the required minimum paste volume for a given workability level. For this purpose, we tried the following experiments: vary the paste volume for the three different grading of aggregates and determine the minimum paste volume to achieve a certain level of workability with high-range water reducing admixture.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.1-6
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• 2015

Recently, lots of researches on concrete with high volume mineral admixture such as ground granulated blast furnace slag (GGBFS) have been carried out to reduce $CO_2$. It is known that the precast concrete has an advantage of high strength at early age due to steam curing, even if concrete has high replacement level of mineral admixture. However it demands the investigation of compressive strength properties according to steam curing regimens. In this study, concretes with water-binder ratio of 32, 35% and water content of 135, 150, $165kg/m^3$ were produced to investigate compressive strength properties of high volume (60% by mass) GGBFS cement concrete according to steam curing regimens. Then steam curing was implemented with the maximum temperature of 50, $60^{\circ}C$ and steaming time of 5, 6, 7 hours. From the test results, it was found that steam curing was effective to raise early strength of high volume GGBFS cement concrete, but 28 day compressive strengths of steam cured specimens were lower than those of water cured specimens. Thus, a further study would be needed for the optimum steam curing regimens to satisfy target demolded strength and specified strength for the application of high volume GGBFS cement concrete to precast concrete members.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.67-69
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• 2012

This paper is to investigate the effect of waste oil on the fundamental properties of high volume fly ash concrete depending on W/B and waste oil contents. Test results reveals that the use of waste oil resulted in an increase of slump and a decrease of air contents due to the presence of emulsion in waste oil. And it is found that the addition of waste oil does not affect the strength development of the concrete significantly.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.133-134
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• 2014

As a previous research, improved durability of concrete by filling capillary pores with waste cooking oil was suggested as a method of controlling carbonation of the concrete replaced high volume of SCMs. on the other hand, the emulsified refined waste cooking oil for better mixing performance had a drawback of reducing air content related with decreasing freeze-thawing resistance. As a solution of this problem, surface applying method was suggested instead of adding in mixing process, and in this research, the performance regarding concrete durability are evaluated comparing emulsified refined cooking oil with water-repelling agent.

• Journal of the Korean Society of Safety
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• v.25 no.5
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• pp.39-43
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• 2010

The surfacing of bridge-decks are object to secure trafficability and to protect bridge face from impact load of traffic volume and other external conditions. But the deformation of pavements and cracks happen due to the damage of the bridge-decks surfacing from the increase of the traffic, short maintenance period and continuous vibration of bridge. This test is to make the 3-type high performance concrete that has different mixing ratio and is added the blast furnace slag, fly ash and silica respectively, and to compare 3-type high performance concrete of normal high strength concrete of $400kgf/cm^2$ strength through the static loading test and fatigue test. And test specimen is united floor slab and pavement for the durability of bridge.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.597-605
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• 2015

The method of concrete mix design used in this study aims to achieve the identical specified design strength, applying different types and replacement ratio of mineral admixtures and afterwards, fire tests were conducted using the standard time-temperature curve specified in the ASTM E119 to identify the influences of the types of mineral admixtures on the fire resistance performance of high strength concrete(HSC). The least spalling was observed in the test specimen containing blast furnace slag as a partial replacement of cement, while the most significant spalling phenomena were observed in the blast furnace slag test specimen that silica-fume was added in. In particular, the reasonable volume of spalling was observed when solely replaced by silica fume. However, the influence of the cement replacement by silica fume and blast furnace slag on the increases of spalling can be explained through blocked pores by the fine particles of silica fume, leading to decreases in permeability.

• Advances in concrete construction
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• v.11 no.2
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• pp.99-109
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• 2021

Slag blended concrete is widely used as a mineral admixture in the modern concrete industry. This study shows an optimization process that determines the optimal mixture of air-entrained slag blended concrete considering carbonation durability, frost durability, CO2 emission, and materials cost. First, the aim of optimization is set as total cost, which equals material cost plus CO2 emission cost. The constraints of optimization consist of strength, workability, carbonation durability with climate change, frost durability, range of components and component ratio, and absolute volume. A genetic algorithm is used to determine optimal mixtures considering aim function and various constraints. Second, mixture design examples are shown considering four different cases, namely, mixtures without considering carbonation (Case 1), mixtures considering carbonation (Case 2), mixtures considering carbonation coupled with climate change (Case 3), and mixtures of high strength concrete (Case 4). The results show that the carbonization is the controlling factor of the mixture design of the concrete with ordinary strength (the designed strength is 30MPa). To meet the challenge of climate change, stronger concrete must be used. For high-strength slag blended concrete (design strength is 55MPa), strength is the control factor of mixture design.