• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.113-116
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• 2006

After laws for recycling promotion of construction wastes was established on December, 2003, successive technical and institutional measures related to construction wastes are driven. Typically quality standards for recycled aggregate were enacted and officially announced, and recently the quality assurance system for recycled aggregate is promoted to be established. In relation, this study reviewed major factors affecting certification examination necessary to carry out quality assurance system for recycled aggregate and related standards to guarantee the quality of recycled aggregate. More specifically it is suggested that working place examination related to manufacturing facility and planning, quality control manpower and system, environmental and safety control, etc, and quality inspection with classified by for road construction, for concrete, and for asphalt concrete are used as quality assurance standards.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.402-407
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• 1996

In this paper, we described the basic elements(flowability, fillingability, elapsed time, pumpability, no-vibrating effects, and etc.) required for the application and quality control of the super flowing concrete (SFC) in construction site. Also, after investigating characteristics of SFC through various experiments, SFC were placed in the reaction wall of large scale structural laboratory in Deawoo Insititute of Construction Technology. As the result of this project, the developed SFC showed high flowability and self-filingability good enough for the requirement. Furthermore, quality control and assurance of the no-vibrating concrete in actual site was verified by various testing.

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.69-76
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• 2001

Foamed concrete for cast-in-site, which shows excellent lightweight, thermal insulation, noise insulation, constructability and cost efficiency, has been applied as thermal insulation or filling material for On-dol. However, the technology is too insufficient to obtain the high level of quality, and serious problems often occur in quality control at sites. It, thus, is necessary to establish the proper and reasonable quality control method for ensuring the required quality, based on the investigation on the physical properties and their reciprocal relation. This study aims to settle the quality control method in case of applying FA foamed concrete replacing 40% by weight with fly-ash as the filling material for On-dol. The results of the study include the correlation among flow, as-placed density and foam ratio of fresh foamed concrete, the correlation between physical properties before hardening and after 28-day, provision of an equation to estimate 28-day compressive strength early with 7-day compressive strength, and suggestion of quality criteria for the revision of KS on foamed concrete for cast-in-site.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.85-86
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• 2016

Recently damages caused by the additional costs and degradation in durability combined deterioration due to plain concrete deterioration has occurred. In particular, in the case of the finish that is not exposed to the outside air in the concrete to respond to the harsh environment (freeze-thawing, calcium laying, etc.), to establish a quality control way for the process and the concrete mix design for it.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.1-9
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• 2015

PURPOSES : The objective of this study is to propose a quality control and quality assurance method for use during asphalt pavement construction using non-destructive methods, such as ground penetrating radar (GPR) and an infrared (IR) camera. METHODS : A 1.0 GHz air-coupled GPR system was used to measure the thickness and in situ density of asphalt concrete overlay during the placement and compaction of the asphalt layer in two test construction sections. The in situ density of the asphalt layer was estimated based on the dielectric constant of the asphalt concrete, which was measured as the ratio of the amplitude of the surface reflection of the asphalt mat to that of a metal plate. In addition, an IR camera was used to monitor the surface temperature of the asphalt mat to ensure its uniformity, for both conventional asphalt concrete and fiber-reinforced asphalt (FRA) concrete. RESULTS : From the GPR test, the measured in situ air void of the asphalt concrete overlay gradually decreased from 12.6% at placement to 8.1% after five roller passes for conventional asphalt concrete, and from 10.7% to 5.9% for the FRA concrete. The thickness of the asphalt concrete overlay was reduced from 7.0 cm to 6.0 cm for the conventional material, and from 9.2 cm to 6.4 cm for the FRA concrete. From the IR camera measurements, the temperature differences in the asphalt mat ranged from $10^{\circ}C$ to $30^{\circ}C$ in the two test sections. CONCLUSIONS : During asphalt concrete construction, GPR and IR tests can be applicable for monitoring the changes in in situ density, thickness, and temperature differences of the overlay, which are the most important factors for quality control. For easier and more reliable quality control of asphalt overlay construction, it is better to use the thickness measurement from the GPR.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.1
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• pp.20-26
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• 2002

To make practical application of mixing test results to concrete mix design, experimental tests of concrete were done and the relationship between cement-water ratio and compressive strength of concrete was obtained. A computer program which can be used for data base of air content, slump and compressive strength test results was developed. The program draws $\bar{X}$-R or X-Rs control charts and has data sheets for arrangement of material test results. The computer program also helps calculation of concrete mix proportions for mixing tests and contains dictionary of concrete technical terms.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.47-52
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• 2000

Recently, it is very necessary the development of the manufacturing techniques for high strength concrete(HSC) for the large-scale size and good quality of civil structure. But, the manufacture and quality control of HSC of which shrinkage, heat of hydration and workability at construction filed are considered, is very difficult due to its low water-cement ratio and high quantity of unit cement content. In the present study, we tried to know and assess the influences of chemical and physical properties of cement on the material properties of HSC. We analyzed basic properties of 4 kinds of cement whose chemical and physical properties are different each other through various tests such as chemical analysis and mortal test. Also, we performed the assessment of the material properties of HSC for each dement by the test for the conditions of same mix design and similar compressive strength. From the results in the study, the assessment of the important quality factors of cement influencing the properties of HSC may be utilized to quality control of applied cement to manufacture the HSC of high quality.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.367-372
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• 2002

The waterproofing systems of concrete bridge deck are installed under the complex circumstances, such as traffic loading, weather, and the condition of the deck concrete. For assuring the effectiveness of waterproofing system, the materials and the construction method and timing ought to be suitably selected with the procedures of waterproofing and the system has to ensure the economical performances. First of all, we discussed whether the quality and performance criteria for highway bridge deck are resonable or not through the investigation of domestic and foreign criteria. The basic properties of waterproofing membranes on market and the performance of waterproofing systems of concrete bridge deck have also been investigated in the view of the damages frequently reported from job site. In this way, the causes and measures of damages, the guidelines of design, construction, quality control, and maintenance, the test methods and criteria of membranes and waterproofing system, are proposed.

• Magazine of the Korea Concrete Institute
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• v.14 no.4
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• pp.14-21
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• 2002

국내에서 시공되는 콘크리트 구조물의 대부분은 레미콘(ready-mixed concrete)으로 시공되고 있기 때문에 레미콘의 품질관리(quality control) 및 품질확보(quality security)는 곧 콘크리트 구조물의 품질과 내구성의 확보를 위해 매우 중요한 사항이다. 최근 콘크리트 구조물의 잦은 사고로 인해 콘크리트의 품질문제가 사회문제로 나타나고 있으며 이에 대비한 콘크리트 품질보증 시스템의 확립이 시급한 실정이다. 그러나 레미콘의 품질환경은 원재료의 품질저하, 레미콘 운반시간의 증대 및 기술개발의 미흡 등 주변여건이 좋은 편은 아니며 레미콘 산업도 경쟁시대에 돌입하면서 레미콘 품질이나 기술우위의 시대로 변화되고 있다.(중략)

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1683-1691
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• 2013

Concrete surface grinding is frequently used for flatness of concrete surface, concrete pavement rehabilitation, and adhesiveness in pavement construction. The procedure is, however, labor intensive and has a hazardous work condition. Also, the productivity and the quality of concrete surface grinding highly depend on the skills of worker. Thus, the development of remote controlled concrete surface grinding equipment is necessary to prevent the environmental pollution and to protect the workers from hazardous work condition. However, it is difficult to evaluate the grinded surface objectively in a remote controlled system. Also, The machine vision system developed in this study takes the images of grinded surface with the network camera for image processing. Then, by representing the quality test results to the integrated program of the remote control station, the quality control system is constructed. The machine vision algorithm means the image processing algorithm of grinded concrete surface and this paper presents the objective quality control standard of grinded concrete surface through the application of the suggested algorithm.