• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.270-271
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• 2014

In this study, a replacement ratio of blast furnace slag coarse aggregate and a water binder ratio by an optimum combination of PHC file was investigated. As a results, the target strength 78.5MPa was altogether satisfied in a mix proportion 28-G100-SG0 and W/B ratio 26 %. The surface rupture was generated in 28-G0-SG100 combination after curing with the autoclave. According to the result of measuring the ingredient, the majority were the MgOH2 hydrate.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.104-111
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• 2004

The aim of this study was to investigate the influence of inorganic pigments on the physical properties of cement mortar. For this purpose, the compressive strength and absorption test were carried out on cement mortar imxed with inorganic pigments by changing the proportion of cement mortar, water-cement ratio, and ratio of pigment. The result of this study can be summarized as follows: the compressive strength of colored mortar rapidely increased in red and yellow mortar, as the mix ratio of pigment increased. In case of green and black mortar, however, the compressive strength decresed as the mix ratio incresed. In case of red and yellow mortar, the absorption of colored mortar increased as the mixing ratio increased, if the mean particle diameter of the pigment is small. In case of green and black mortar, the absorption ratio decreased as the mix ratio increased. After investigating the overall physical properties of colored mortar, it was confirmed that the proper mix ratio of pigment securing the properties of colored mortar was below 6% of the weight of the cement to be used.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.63-70
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• 2015

PURPOSES: As a part of our research into repair techniques for roads that have collapsed as a result of a natural disaster, this study set out to find the optimum mix proportion for gravels to be used to restore a damaged area. METHODS: This study considered flow and strength-development characteristics. The experimental variables were the W/C ratio, the usage of the admixture, the types of cement, and the quantity of fine aggregate over three different experimental stages. The compressive strength was measured at 12 hours, one day, three days, and seven days. RESULTS : The flow varied with the amount of fine aggregate and the use of a high-range water-reducing (HRWR) admixture. The compressive strength also varied with respect to the type of cement and the W/C ratios. The strength satisfied the expected requirement of 21 MPa after one day, provided the mix proportion was appropriate. CONCLUSIONS: A gravel-filling high-flow cement-based mortar exhibited strength and consistency with a W/C ratio in the range of 0.40 to 0.45, assuming the use of HRWR at 0.5 to 0.7% and a fine aggregate/cement ratio of 1.0 to 1.5.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.180-185
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• 1996

Construction activities and operation of transportation facilities have caused unfavorable effects such as civil petitions associated with vibration-induced damages or nuisances. The objedtive of this research is to develop vibration-controlled concrete containing foams, latex, rubber powders, plastic resins and etc as a concrete mixture. As the first step to achieve this research, preliminary mix designs have been carried out to find out an appropriate mix proportion above 200kg/㎠ in uniaxial compressive strength, and investigate their dynamic mechanical characteristics such as dynamic elastic moduli, material damping ratio, Poisson's ratio, resonant frequency and etc.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.549-554
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• 2002

In Powder System, SCC demands high dosage of superplasticizer and a lage amout of powder for suitable fluidity and viscosity. Okamura's method of most representative mixing design method in SCC of Powder-System is unfavorable economically because of using a large amount of powder. In addition, many ready-mixed concrete plants do not use his mix design method and procedure due to complexity for practical application. Therefore, Nan Su proposed more simple mix design method than Okamura's. It had an advantage in simplicity in practical application and required a smaller amount of powders compared with Okamura's method. This paper proposed an optimal mixture proportion of SCC with consideration of Nan Su's method. The new and modified mix design method required a smaller amount of powder than that of Nan Su's. To check the properties of SCC, considered with the requirements specified by the Japanese Society of Civil Engineering.(JSCE)

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.103-110
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• 1997

The objective of this study is to provide the information on the small-scale model mix proportion when the behavior of prototype concrete pavement is studied through small-scale model experiments. However it is difficult to obtain a model material to simulate the prototype concrete by scaling the individual components according to the laws of similitude. In this paper, the stress-strain behavior in uniaxial compression is used as a means to correlate materials similitude between the prototype and the model concrete. Based on th results of experiments, We compared the stress-strain curves of prototype and model concrete mixes using a nondimensional basis. In order to simulate the stress-strain curves of prototype concrete, it is important that various mix as of model concrete selected properly which are varied from aggregate grading, cement-aggregate and sand-aggregate ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.11a
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• pp.49-52
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• 2003

The objective of this study the mechanical characteristics of prefoamed lightweight foamed concrete using the mineral foam agent which has high lightness, and strength. The compressive strength of lightweight foamed concrete using mineral foam agent are about 2 times degree high those the of lightweight foamed concrete using vegetable foam agent. Lightweight foamed concrete was able to obtain the result of 50kg/㎠ or more compressive strength, when was unit weight 0.8t/㎡. In the case of the same unit weight of concrete, it is influenced by w/c of foam agent ratio. The paper present extensive data on characteristics of compressive strength of the concrete manufatured with the different factors in mix design and also present optimum mix proportion.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.49.1-52
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• 2003

The objective of this study the mechanical characteristics of preformed lightweight foamed concrete using the mineral foam agent which has high lightness, and strength. The compressive strength of lightweight foamed concrete using mineral foam agent are about 2 times degree high those the of lightweight foamed concrete using vegetable foam agent. Lightweight foamed concrete was able to obtain the result of 50kg/$\textrm{m}^3$ or more compressive strength, when was unit weight 0.8t/$\textrm{m}^3$. In the can of the same unit weight of concrete, it is influenced by w/c of loan agent ratio. The paper present extensive data on characteristics of compressive strength of the concrete manufactured with the different factors in mix design and also present optimum mix proportion.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.131-132
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• 2011

This study analyzes the yearly-best delivered size range of truck mixer based on the specified mix, Water to Binder Ratio, aggregate proportion and unit amount with statistical method targeting on Kyeongi and Kyeongsang province and compares with the similar materials of Japan to propose as a basic standard for the quality control of mixer truck. As a result, in case of the Water to Binder Ratio of these areas, it is higher than Japan's due to the excessive safety rate reflecting the changes of differential value impact and unit amount, and the unit amount's standard deviation is very large by reflecting the changes of the amount used and chemical admixture susceptibility. In case of aggregate proportion, the frequency rate is about 50%, which is very similar value with Japan's one.

• KCI Concrete Journal
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• v.14 no.3
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• pp.121-129
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• 2002

This study investigates experimentally into the design factors and quality variations having an effect on the properties of the combined high flowing concrete to be poured in the slurry wall of Inchon LNG in-ground receiving terminal. Especially, high belite cement and lime stone powder as cementitious materials and viscosity agent in order to improve self-compaction and hydration heat are used in this study. Water-cement ratio(W/C), fine aggregate volume ratio(Sr) and coarse aggregate volume ratio(Gv) as design factors of the combined high flowing concrete are applied to determine the optimum mix design proportion. Also quality variations for sensitivity test are selected items as followings. (1)Surface moisture(5cases) and (2)Fineness modulus of fine aggregate(5cases), (3)Concrete temperature(3cases), (4)Specific surface(3cases) and particle size of lime stone powder. As experimental results, water-cement ratio, fine and coarse aggregate volume ratio are shown as the optimum range 51%, 43% and 53% separately considering site condition of slurry wall. Also quality factors by sensitivity test should be controlled in the following ranges. (1) Surface moisture :to.67% and (2)Fineness modulus 2.6$\pm$0.2 of fine aggregate, (3)Concrete temperature l0-20t, (4) Specific surface 6,000$\textrm{cm}^2$/g and particle size 9.7$\pm$1.0${\mu}{\textrm}{m}$ of lime stone powder. Based on the results of this study, the optimum mix design proportion of the combined high flowing concrete are selected and poured successfully in the slurry wall of LNG in-ground tank.