• Journal of the Korea Institute of Building Construction
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• v.18 no.2
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• pp.133-140
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• 2018

The objective of this study is to propose a reliable mixing design procedure of concrete using artificial lightweight aggregate produced from expanded bottom ash and dredged soil. Based on test results obtained from 25 mixes, empirical equations to determine water-to-cement ratio, unit cement content, and replacement level of lightweight fine aggregates were formulated with regard to the targeted performance (compressive strength, dry density, initial slump, and air content) of lightweight aggregate concrete. From the proposed equations and absolute volume mixing concept, unit weight of each ingredient was calculated. The proposed mix design procedure limits the fine aggregate-to-total aggregate ratio by considering the replacement level of lightweight fine aggregates, different to previous approach for expanded fly ash and clay-based lightweight aggregate concrete. Thus, it is expected that the proposed procedure is effectively applied for determining the first trial mixing proportions for the designed requirements of concrete.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.652-660
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• 2008

For the recycling of rapid-chilled steel slag, the mechanical strengths and physical properties of EVA-polymer modified mortars with the various replacement ratios of rapid-chilled steel slag were investigated. Twenty five specimens of polymer modified mortars were prepared with the five different amounts of EVA-polymer modifier (0, 5, 10, 15, 20 wt%) and rapid-chilled steel slag (0, 25, 50, 75, 100 wt%). For the investigation of the characteristics of polymer modified mortars, the measurements such as water-cement ratio, unit volume weight, air content for fresh mortar and compressive strength, flexural strength, water absorption, hot water resistance, porosity and SEM investigation for curing specimens were conducted. As a results, with an increase in the replacement ratio of rapid-chilled steel slag, water-cement ratios decreased but unit volume weight increased remarkably. With increasing EVA-polymer modifier and the replacement ratio of rapid-chilled steel slag, percent of water absorption decreased but compressive and flexural strengths increased remarkably. By the hot water resistance test, mechanical strengths decreased but total pore volume and porosity increased remarkably. In the SEM observation, the components of specimen were shown to stick to each other in the form of co-matrix phase before hot water resistance test, but polymer modifier of co-matrix phase was decomposed or deteriorated after hot water resistance test.

• Korean Journal of Agricultural Science
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• v.32 no.1
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• pp.19-27
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• 2005

This study was performed to evaluate the physical and mechanical properties of polymer concrete using unsaturated polyester resin, initiator, heavy calcium carbonate, crushed gravel, recycled coarse aggregate, silica sand and recycled fine aggregate. The unit weight, compressive strength, flexural strength and dynamic modulus of elasticity were decreased with increasing the content of recycled aggregate. The unit weight, compressive strength, flexural strength and dynamic modulus of elasticity were showed in $2,127{\sim}2,239kg/m^3$, 80.5~88.3MPa, 19.2~21.5MPa and $254{\times}10^2{\sim}288{\times}10^2MPa$ at the curing age 7 days, respectively. Therefore, these recycled aggregate can be used for polymer concrete.

• Magazine of the Korea Concrete Institute
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• v.2 no.3
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• pp.81-88
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• 1990

For the protectioon of radioactive leakage, the quality control of main concrete structure in nuclear power plants is very important. So, this studey is designed to analyze the influence of kind of cement and aggregate on the mechanical properties of high density concrete. Test results of this study are as follows; 1)The slump of magnetite aggregate concrete(MAC) is found half value of nat.ural aggregate concrete (NAC). 2)As the effect of cement, the compressive strength of concrete using moderate heat cement is found higher 5-19 % than that of ordinary portland cement. 3)As the effect of fine aggregate, t.he compressive strength of MAC is found higher than that. of NAC below 340kg/$cm^2$ and lower t.han NAC above 340kg/$cm^2$. 4)As the effect of coarse aggregate, the compressive strength of MAC is found higher 17-22% than that of NAC.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.577-580
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• 2008

This paper was discussed about in-site application of heavyweight(or high density) concrete. Heavyweight concrete was placed with the method of conventional. Placement of conventionally mixed heavyweight concrete is subject to the same considerations of quality control as normal density concrete, except that it is far more susceptible to variations in quality due to improper handling. It is particularly subject to segregation during placement. Segregation of heavyweight concrete results not only in variation of strength but, far more importantly, in variation in density that are intolerable for work this type, since this adversely affects shielding properties. Heavyweight concrete materials and heavyweight concrete should be sampled and tested prior to and during construction to insure conformance with applicable standards and specifications.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.55-56
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• 2015

This study is corroborated as a fundamental resource to develop structural lightweight paste containing silica fume as a part of cement. Paste using foaming agent is generated much foam and decreased density of paste. This study is measured at 0.8% of foaming agent dosage but over 0.8% of foaming agent dosage raise density of paste because of interconnection with foam. Also, FEM analysis using SEM image is confirmed correspondence of between Elastic modulus of experiment and FEM analysis.

• Journal of the Korea Concrete Institute
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• v.21 no.3
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• pp.283-290
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• 2009

Differently from fly ash, the bottom ash produced from thermoelectric power plant has been treated as an industrial waste matter, and almost reclaimed a tract from the sea. If this waste material is applicable to foam concrete as an aggregate owing to its light-weight, however, it may be worthy of environmental preservation by recycling of waste material as well as reducing self-weight of high-rising structure and horizontal forces and deformations of retaining wall subject to soil pressure. This study has an objective of evaluating the effects of application of bottom ash on the mechanical properties of foam concrete. Thus, the ratio of bottom ash to cement was selected as a variable for experiment and the effect was measured in terms of unit weight of concrete, air content, water-cement ratio and compressive strength. It can be observed from experiments that the application ratios have different effects on the material parameters considered in this experiment, thus major relationships between application ratio and each material parameter were finally introduced. The result of this study can be applied to decide a mix design proportion of foam concrete while bottom ash is used as an aggregate of the concrete.

• KIEAE Journal
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• v.13 no.6
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• pp.137-143
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• 2013

The purpose of this study is to suggest optimum micro-filler experiment method to select the optimal particle size of earth for using in earth construction works and test this suggestion through compressive strength measurement. According to the results of selecting the method to choose the optimum micro-filler mixing of earth and sand, three-stage filling(plate tamping) showed relatively high results and so was estimated to be the proper filling method. According to the results of optimum micro-filler experiment of earth and sand by the maximal sizes of sand, between 80% and 90% showed the highest result values. The larger the maximum size of sand was, the lower the addition ratio of sand was in optimum micro-filler mixing. According to the results of compressive strength experiment by the particle sizes of earth and sand, 90% in the addition ratio of sand showed the highest results, and so tended to be similar to the results of unit volume weight experiment.

• Clean Technology
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• v.12 no.4
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• pp.238-243
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• 2006

The aggregate properties of chilled converter slag reformed by atomizing liquid converter slag were investigated. The properties of mortars with various replacement of standard sand by chilled converter slag as recycled fine aggregates were investigated. The particle shape of chilled converter slag by atomizing was a sphere with an open cavity which is enclosed with two layers like a bored coconut. Specific gravity, unit weight and fineness modulus increased with increasing the replacement, and solid content had the maximum at the replacement of 75% and water absorption rate had the minimum at the replacement. The hardened mortars with higher replacements have the higher specific gravity and the denser texture.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.1
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• pp.39-43
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• 2015

The cement mixtures such as flyash, iron-slag and silica fume have been actively studied in order to increase the quality of concrete. In this study, the grinded copper-slag with different proportion was added to portland cement. The physical properties of the cement mortars, (i.e.) flowability, absorption, compressive strength and flexural strength, were investigated for the potential application to the cement. Also, the influence of the acid on the chemical resistance of the cement mortars with copper-slag was evaluated by monitoring the weight variation of the cement mortars under 5 % sulfuric acid for 28 days.