• Advances in Computational Design
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• v.8 no.2
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• pp.113-131
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• 2023

The use of fibers has been commonly considered in engineered cementitious composites, but their behavior with coarse aggregate in concrete has not been studied significantly, which is needed to meet structural performance objectives for design, such as ductility. This research analyzes the behavior of fiber-reinforced concrete with coarse aggregate with 0.62%, 1.23%, and 2% PVA (Polyvinyl-alcohol) content, varying the maximum aggregate size. Tensile (direct and indirect) and compressive concrete tests were performed. The PVA fiber addition in coarse aggregate concrete increased the ductility in compression, especially for the fiber with a larger aspect ratio, with a minor impact on strength. In addition, the tensile tests showed that the PVA fiber increased the tensile strength of concrete with coarse aggregate and, more significantly, improved the ductility. A selected mixture was used to build short and slender reinforced concrete beams to assess the behavior of structural members. PVA fiber addition in short beams changed the failure mode from shear to flexure, increasing the deflection capacity. On the other hand, the slender beam tests revealed negligible impact with the use of PVA.

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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• pp.121-128
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• 2010

This is to show some basic data for introducing both circulated aggregate and recycled powder producing waste concrete. Standard-mixing design for 24MPa has been basically used and added and replaced normal aggregate with recycled powder made of waste concrete. In addition, polycarboxylate high-range water reducing agent has been used because recycled powder is missing adhesive strength and it is not compare with cement's adhesive strength. Compressive strength with powder mixture of 2%, 4%, 6%, 8%, and 10% has been decreased down to 80% of normal concrete material strength without recycled powder mixture. $200^{\circ}C$, $400^{\circ}C$ and $600^{\circ}C$ heated concrete were compressively tested in order to find out concrete strength resistant to high temperature. heat capacity was also tested, based on the expectancy of its low conductivity. In addition, thermal conduction test was tested in order to find out concrete insulation. According to this test, when concrete was tested by fire resistance, it using the circulation aggregate was same resulted by concrete using the natural aggregate. also, recycle powder was not effecting insulation performance. but it is fit to standard on concrete insulation of building law.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.369-372
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• 2000

This investigation aims at the optimum mixing of flexible flowable-fill made of Bottom-ash as an industrial waste. Flowable-fill refer to self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. The two primary advantages of flowable fill over traditional methods are its ease of placement and the elimination of settlement. Therefore, in difficult compaction areas or areas where settlement is a concern, flowable fill should be considered. This study compares Bottom-ash with fine aggregate in physical character. The mixing design indicates a various mixing-rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6534-6541
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• 2013

The aim of this study was to develop a fiber-reinforced asphalt mixture that was designed to do the following: 1) address fatigue cracks, which is a major source of damage; and 2) increase the rutting resistance. This study reports the effects of the aggregate mixture design that incorporates a dumbbell-shaped fiber. An experiment was carried out to measure the unit weights and unit weight ratios between the mixture that was compacted and the one that was not. A method to substitute a specific aggregate mixture with the dumbbell-shaped fiber was confirmed using the volume concept according to the Bailey method. The results showed that the weight of the PCS aggregate mixture that need to be replaced was 11.88g when a 0.3% reinforcing fiber was added to the 1950g mixture.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.3
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• pp.58-69
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• 1996

In recent years, the research and development about the new material proceeds rapidly and actively. In building industry, high strength concrete is of interest as a new material. Since the building structure becomes bigger, higher and more specialized, the demand of material and member with high strength expands greatly. Therefore in this experiment, cement complex with high strength was made using the condensed silica fume, a basic experiment was performed on strength property, and optimum-mixture-state was determined for manufacturing a high-strength concrete. Shear behaviour and fracture property of concrete beams with high strength were evaluated. On the whole, in spite of many researches, it is one of the difficult problems that shear fracture of concrete beams has not yet been clearly understood theoretically, and now the shear-design-standard forms in many countries are a formula based on experiment. In this study, the variable of shear behavior experiment was shear-reinforcement-ratio. By analyzing test results and comparing with computation value by ACI code, the basic data was offered on shear design of reinforced concrete beams with high strength. The effect of epoxy repair was also investigated for the beams with cracks due to flexural and shear loading.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.491-497
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• 2013

The objective of the present study is to establish a straightforward mixture proportioning procedure for structural lightweight aggregate concrete (LWAC), and evaluate the selection range of the targeted dry density of concrete against the designed concrete compressive strength. In developing this procedure, mathematical models were formulated based on a nonlinear regression analysis over 347 data sets and two boundary conditions of the absolute volume and dry density of concrete. The proposed procedure demonstrated the appropriate water-to-cement ratio and dry density of concrete to achieve the designed strength decrease with the increase in volumetric ratio of coarse aggregates. This trend was more significant in all-LWAC than in sand-LWAC. Overall, the selection range of the dry density of LWAC exists within a certain range according to the designed strength, which can be obtained using the proposed procedure.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.67-74
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• 2012

PURPOSES: In this study the influence factors related to abrasion resistance of interlocking concrete block have been evaluated, and comparisons between various domestic and foreign abrasion test methods was also accomplished. METHODS: The modified rotational cutting method suggested in ASTM C 944 was applied. Surface materials with different types of fine aggregate such as crushed sand, sea sand, and mixture of crushed and sea sand were tested to compare the aggregate effect for abrasion resistance. RESULTS: The different surface mixtures with various W/C ratios, mortar and fly ash ratios have been investigated for functional and economical considerations. CONCLUSIONS: This study had obtained reliable results by changing diamond blade of rotating cutter. Therefore, in order to improve the abrasion resistance of interlocking concrete block for road, a new mix design was proposed.

• Journal of the Korea Institute of Building Construction
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• v.3 no.4
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• pp.135-138
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• 2003

The purpose of this study was to design the self-compaction concrete mixture, having not only high strength but also compensation of shrinkage without thermal crack under 4 sides outer restraint of the member. In the experimental mix, replacement ratio of limestone Powder, CSA expansive additives, and unit water were selected as parameters, using portland blast-furnace slag cement. And, bleeding test, expansibility test, hydration heat analysis were performed. As a results, when 35% of limestone Powder, 6% CSA expansive additives are replaced at unit water 175kg/$\textrm{m}^3$, demanded performances of fresh and hardened self-compaction concrete are accomplished.

• Journal of the Korea Institute of Building Construction
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• v.4 no.1
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• pp.85-88
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• 2004

The purpose of this study was to design the self-compaction concrete mixture, having not only high strength but also compensation of shrinkage without thermal crack under 4 sides outer restraint of the member. In the experimental mix, replacement ratio of limestone Powder, CSA expansive additives, and unit water were selected as parameters, using portland blast-furnace slag cement. And, bleeding test, expansibility test. hydration heat analysis were performed. As a results, when 35% of limestone Powder, 6% CSA expansive additives are replaced at unit water 175kg/$\textrm{m}^3$, demanded performances of fresh and hardened self-compaction concrete are accomplished.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.191-198
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• 1999

The purpose of this study is investigating characteristics of the concrete containing Fly-ash according to different 4 mix design, that is, the first mix design is partial replace Fly-ash of cement, second is partial replace Fly-ash of cement and fine aggregate, third is partial replace Fly-ash of fine aggregate, fourth partial replacement of fine and coarse aggregate. For this purpose, selected test variables were water-binder ratio with two levels of 45%, 50%, and Fly-ash contents with four levels 0%, 10%, 20%, 30%, As the result of this study are as follow. 1) The result of mix design of a partial replacement of cement, the slump-flow value was appeared a promotive effect of viscosity. But in case of the over with Fly-ash 10% and the other mix design was not changed slump value. 2) The unit weight of the mixing rate with Fly-ash 0% was $1.875{\sim}1.884t/m^3$, the other mix design 10% over with Fly-ash was $1.846{\sim}1.615t/m^3$, the difference was appeared less about 15% than that. 3) In design, partial replace Fly-ash of fine aggregate, this compressive strength was appeared that the concrete age after 7 days was higher than in partial replacement of cement, therefore, the default of a concrete with Fly-ash, that is the earlier compressive strength was to lessen, was improved. 4) The thermal conductivity of the all mix design was $0.447{\sim}1.144kcal/mh^{\circ}C$, this value was as good as a lightweight aggregate concrete.