• International Journal of Highway Engineering
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• v.20 no.1
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• pp.59-67
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• 2018

PURPOSES : This paper presents a mix design method for using steel slag as an aggregate for asphalt mixtures. METHODS : Steel slag has a different density and absorption rate than natural aggregates. The asphalt content was calculated according to the steel slag characteristics, and the formula for aggregate-gradation correction was presented. RESULTS : The asphalt mix was designed using the proposed equations. Using the proposed mix design method, it was possible to design the asphalt mixture according to the target-usage amount of the recycled aggregate. CONCLUSIONS : The suggested method can be used for asphalt mix design using aggregates with different densities and absorption rates. It is expected to contribute to quality improvement by ensuring accurate calculation of mixing ratios for steel slag asphalt mixtures.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.25-33
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• 2013

In this study, the optimum mix proportions of rain garden structure concrete were decided and the mechanical properties were evaluated. Experimental parameters were blast furnace slag, hwang-toh, recycled aggregates and natural jute fibers. The target compressive strength and chloride ion penetration were more than 24 MPa and less than 1000 coulombs, respectively. The response surface method was used for statistical optimization of experimental results. The optimal mixing ratios of the blast furnace slag, hwang-toh, recycled coarse aggregate and jute fiber volume fraction were determined 59.98 %, 8.74 %, 12.12 % and 0.2 %, respectively. The compressive strength, flexural strength and chloride ion penetration test results of optimum mix ratio showed that the 24.56 MPa, 3.88 MPa and 999.08 columbs, respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.212-213
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• 2018

The cementitious composites have been developed to satisfy various demands of the construction market. The conductive concrete, which is a carbon-based cementitious composite, was used for the deicing or the detecting the internal crack. The cement-based battery is a technology that applies the basic concept of the alkaline battery to these conductive concretes. The cementitious composites could have a function as batteries, through a mixing of anode and cathode, which were consist of the zinc and manganese dioxide powder. The carbon-based materials, which have a significant effect on electrical properties, could be considered as the main variable in cement-based batteries. Therefore, in this study, the effects of carbon-based materials were investigated. Two types of materials, including the Carbon black and Multi-walled carbon nanotube(MWCNT), were considered as the main variables. From the experiment results, the electrical characteristics such as resistance, voltage, and current were compared according to the age.

• Proceedings of the Korea Concrete Institute Conference
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• 1992.04a
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• pp.35-40
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• 1992

Results of an experimental study on the manufacture, the workability and mechanical properties of steel fiber reinforced polyester resin composites utilizing industrial waste products are presented in this paper. The fly ash polyester resin composites using steel fiber, fly ash and calcium carbonic acid (CaCo3), unsaturated polyester resin, styrene monomer, cobalt octate and methyl ethyl ketone peroxide, fine and coarse aggregates are prepared with various filler~binder rations, binder rates and mixing conditions. As a test results, the workability of steel fiber reinforced polyester resin composites are considerably dropped with increasing fly ash-binder ratio and steel fiber volume. And compressive, flexural strength and bending toughness of the composites are remarkably improved with augmenting fiber contents.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.277-280
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• 2005

Epoxy-mortar composites have been wildly used as finishing and repairing materials in the construction because of their excellent properties. Conventional epoxy-mortars and concretes have an inferior applicability and cost performance ratio due to the two component mixing of the epoxy resin and hardener. In this study, we examined the engineering effect of compressive strength and flexible strength according to the various epoxy-hardener in underwater and humidity environment, and evaluated the hardener types and physical effect of Epoxy mortar using cement binder in underwater and air condition. In this study, it was clarified that the engineering properties of repairing epoxy-motars were effected by the type of hardener.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.23-24
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• 2018

Reinforced concrete is a building material that is generally used in modern society. Also, reinforced concrete structures in high salinity environments have low durability due to corrosion of reinforcing bars due to infiltrated chlorine ions. Anion exchange resins have an ability to immobilize chlorine ions in the resin while releasing their anions. As a material, it has already been shown that it is possible to fix the chloride ion inside the cementitious material through the cement mortar experiment. The purpose of this study is to confirm the compressive strength of cement mortar using powdered anion exchange resin after powdering an anion exchange resin. In order to confirm the chloride ion fixation ability of the powder anion exchange resin, chlorine ion penetration resistance test was carried out.

• KCI Concrete Journal
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• v.11 no.3
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• pp.65-77
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• 1999

A portland cement was reinforced by incorporating carbon fiber(CF), silica powder, and impregnating the pores with styrene monomers which were polymerized in situ. The effects of type, length, and volume loading of CF, mixing conditions, curing time and, curing conditions on mechanical behavior as well as freeze-thaw resistance and longer term stability of the carbon-fiber reinforced cement composites (CFRC) were investigated. The composite Paste exhibited a decrease in flow values linearly as the CF volume loadings increased. Tensile, compressive, and flexural strengths all generally increased as the CF loadings in the composite increased. Compressive strength decreased at CF loadings above approx. 3% in CFRC having no impregnated polymers due to the increase in porosity caused by the fibers. However, the polymer impregnation of CFRC improved all the strength values as compared with CFRC having no Polymer impregnation. Tensile stress-strain curves showed that polymer impregnation decreased the fracture energy of CFRC. Polymer impregnation clearly showed improvements in freeze-thaw resistance and drying shrinkage when compared with CFRC having no impregnated polymers.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.329-332
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• 2004

This study aims to manufacture non-sintering cement(NSC) by adding phosphogypsum(PG) and waste lime(WL) to granulated blast furnace slag(GBFS) as sulfate and alkali activators. This study also investigates the pore structure of NSC Matrix. The result of experiment of pore structure properties, showed no considerable difference for total pore volume by cement mixing ratio but shows a large distinction in distribution of pore diameter. On the whole, pore-diameter of paste of NSC show that occupation ratio of pore diameter below 10mm is larger and is smaller than OPC and BFSC at pore diameter of over 10nm. Such a reason is that the hydrate like CSH gel and ettringite formed dense pore structure of NSC matrix.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.731-734
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• 2004

Admixture compounds for reducing setting time and accelerating early strength development of redispersible polymer powder-modified mortars were made by mixing various inorganic accelerating inorganic materials. Redispersible polymer powder-modified mortars are prepared with various accelerator contents, and it was tested for setting time, flexural and compressive strengths. As a result, the accelerators contribute to strength development of the mortars in the early curing age of 12h or less. In the viewpoint of early strength development of redispersible polymer powder-modified mortars, an accelerator content of $20\%$ is recommended.

• 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.