• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.5
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• pp.59-67
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• 1998

The object of this study is to investigate the strength characteristics and the freeze-thaw resistance of high strength concrete incorporating fine blast furnace slag. Major experimental variables were the water/cement ratio, maximum size of coarse aggregate, and cement types such as ordinary portland and slag cement. The results were as follows ; The workability of fresh concrete incorporating fine blast furnace slag was better than that of OPC(ordinary Portland cement) in terms of slump. The freeze-thaw resistance showed better than that of OPC, keeping more than 90% of relative modules of elasticity after 506 cycles and showing only a hair crack at surface without serious damage. Thus, the fine blast furnace slag might be recycled at concrete to make high strength concrete at fields.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.4
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• pp.21-27
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• 2009

This study was performed to evaluate the physical and mechanical properties of porous concrete using waste activated carbon. Material used were ordinary portland cement, recycled coarse aggregate, waste activated carbon and superplasticizer. The replacement ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9, and 10 %. The void ratio was decreased and ultrasonic pulse velocity was increased with increasing the waste activated carbon powder, respectively. The compressive strength and flexural strength of porous concrete using waste activated carbon powder were in the range of 8.21${\sim1}$6.58 MPa and 1.69${\sim1}$3.68 MPa, respectively. The pH degree of porous concrete in 1day and 77days were shown in 12.50${\sim1}$12.63 and 10.21${\sim1}$10.70, respectively. Accordingly, waste activated carbon can be used for porous concrete material.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.4
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• pp.23-30
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• 2006

This study is performed to evaluate flowability of high flowable concrete using ordinary portland cement, crushed coarse aggregate, crushed sand, sea sand, fly ash, lime powder and superplasticizer. The slump flow and air content are increased with increasing the content of lime powder. But, the O-type funneling time and Box-type passing are decreased with increasing the content of lime powder. The slump flow, air content, O-type funneling time, Box-type passing and L-type filling of target compressive strength 21-27 MPa and 35-42 MPa at curing age 28 days are 47-50 cm and 56-60 cm, 4.2-5.5% and 4.0-5.7%, 8-12s and 5-10s, 4.3-5.0 cm and 3.4-5.0 cm, and excellent, respectively. These concrete can be used for high flowable concrete.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.123-128
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• 2013

This study was performed to evaluate the slump flow, air content, setting time, compressive strength, adiabatic temperature rise and diffusion coefficient of chloride used ordinary portland cement, crushed coarse aggregate, crushed sand, river sand, fly ash, limestone powder, blast furnace slag powder and superplasticizer to find optimum mix design of low carbon green concrete for structures. The performances of low carbon green concrete used fly ash, limestone powder and blast furnace slag powder were remarkably improved. This fact is expected to have economical effects in the manufacture of low carbon green concrete for structures. Accordingly, the fly ash, limestone powder and blast furnace slag powder can be used for low carbon green concrete material.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.9-10
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• 2016

This study is purposed to review the confirm method of pumping efficiency using the concrete flow table test in Korea environment. This test method is registered as the "EN 12350-5, Testing fresh concrete. Flow table test" in Eurocode. When applying this test in the Korea construction environment, we reviewed that reasonably apply on the Korean construction Environment. As a result, test results analysis showed that the reality looks a big difference. Its cause is believed to be due to the shape of coarse & fine aggregate. But it will be better predict method, through the correlation analysis of construction data and the standard(Placing Concrete by pumping Methods(ACI Manual of concrete Practice 304.2R-96)).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.130-131
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• 2018

The compressive strength of concrete is determined by various influencing factors. However, the conventional method for estimating the compressive strength of concrete has been suggested by considering only 1 to 3 specific influential factors as variables. In this study, nine influential factors (W/B ratio, Water, Cement, Aggregate(Coarse, Fine), Fly ash, Blast furnace slag, Curing temperature, and humidity) of papers opened for 10 years were collected at 4 conferences in order to know the various correlations among data and the tendency of data. The selected mixture and compressive strength data were learned using the Deep Learning Algorithm to derive an estimated function model. The purpose of this study is to investigate the effect of the number of hidden layers on the prediction performance in the process of estimating the compressive strength for an arbitrary combination.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.271-276
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• 1999

This study is performed to evaluate an elastic properties and acid-resistance of concrete using pine needle ash(PNA). Materials used for this experiment are PNA , normal portland cement, natural fine and coarse aggregate. Test results show that the highest ultrasonic pulse velocity , dynamic and static modulus of elasticity is achieved by 5% PNA filled PNA concrete, which has showed similar with those of thei normal cement concrete. Acid-resistance of PNA concrete is increased with increase of the contnet of PNA , it is 1.29 times of the normal cement concrete by 5% PNA fille PNA concrete an d2.57 times by 15% PNA filled PNA concrete . Accordingly , PNA concrete wil greatly improve the properties of concrete.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.11-17
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• 2013

This study was performed to evaluate the chlorine ion penetration resistance, chemical resistance and freezing and thawing resistance used ordinary portland cement, crushed coarse aggregate, crushed sand, river sand, fly ash, limestone powder, blast furance slag powder and superplasticizer to find optimum mix design of low carbon green concrete for structures. The performance of low carbon green concrete used fly ash, limestone powder and blast furnace slag powder were remarkably improved. This fact is expected to have economical effects in the manufacture of low carbon green concrete for offshore structures. Accordingly, the fly ash, limestone powder and blast furnace slag powder can be used for offshore structure materials.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.365-368
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• 2005

Waste concrete powder(WCP) has been estimated with a great value-added material as by-product of waste concrete manufactured to fine and coarse aggregate for concrete, because it is able to utilized for cement clinker and concrete admixture. Experimental tests were performed as such plastic viscosity of paste, flow and compressive strength of mortar by surface area of WCP. As a result, flow and 28days compressive strength of mortar was decreased according to increased replacement ratio of WCP as compared to control mortar. Also, plastic viscosity of paste used WCP1 and WCP2 was decreased with increasing replacement ratio, but WCP3 was increased with increasing replacement ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.73-74
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• 2015

As this study is one related to ultra high strength concrete using crushed coarse limestone aggregates among the series of experiments for improving the economic inefficiency of the ultra high strength concretes used for high rise structures, it has analyzed the flowability of ultra high strength concrete according to the variation of blended fine aggregates. As a result of analyzing the characteristics of fresh concrete, it is determined that the application of ultra high strength concrete would be difficult in case of a mix using blended fine aggregates as lower flowability than the mix using limestone crushed fine aggregate only was shown in all mixes using blended fine aggregates.