• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.211-212
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• 2022

In this study, the cracking control performance of ultra-low shrinkage concrete was investigated by the field application. As a result, drying shrinkage crack occurred in normal concrete wall, but no crack occurred in ultra-low shrinkage concrete wall. It is determined that the drying shrinkage crack control effect of the ultra-low shrinkage concrete is excellent.

• Journal of the Korean Wood Science and Technology
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• v.14 no.2
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• pp.36-42
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• 1986

Both the control and heated specimen of oak, hornbean, alder, poplar, red pine and pitch pine among domestic commercial species and taun imported were used for radial and tangential shrinkage and movement that occurred on changing the relative humidity of the atmosphere from 90 percent to 60 percent at $25^{\circ}C$. The results of this study were as follows. 1. The radial and tangential shrinkage of the control and heated hornbean and oak wood, except alder, of high specific gravity showed greater than species with low specific gravity. The ratio of tangential to radial shrinkage was 1.46 for taun to 2.70 for alder. Green volume specific gravity of the heated and soaked specimen of all species except poplar decreased 1.5 to 3.1 percent. Shrinkage of the heated specimen increased more than that of the control specimen, and antishrink efficiency of all timbers except alder had negative value. Shrinkage from green to air dry of treated specimens increased more than case of total shrinkage, and radial shrinkage of those specimen increased greater than tangential shrinkage. 3. The movement of the heating specimen for 120 hours decreased than those of the control and the heating specimen for 240 hours. The movement of heating oak, poplar, red pine and pitch pine (or 240 hours increased rather than those of the control specimen.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.148-149
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• 2021

In Japan, ultra-low shrinkage concrete has been developed and commercialized to control drying shrinkage cracks to the limit. However, in the case of South Korea, the study on this technology has not yet been conducted in earnest. Therefore, the study was conducted for the development of ultra-low shrinkage concrete to control the drying shrinkage crack of concrete to the limit, and in this study, after determining the mixture of ultra-low shrinkage concrete, a wall type mock-up specimen was produced to observe the shrinkage behavior of ultra-low shrinkage concrete.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.124-131
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• 2001

The shrinkage properties of high early strength concrete were investigated. One of the method to control microcrack and crack development due to restrained shrinkage is to reinforce concrete with randomly distributed fibers. Regulated-set cement and two different types of fiber were adopted. The experiments for heat of hydration, drying and autogenous shrinkage were conducted. The desirable resistance of high early strength fiber reinforced concrete to restrained shrinkage microcracking was achieved. These results indicate that use of fiber in high early strength concrete plays an important role in control of crack development due to restrained shrinkage.

• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.45-55
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• 2022

Ultra-low shrinkage concrete is very effective for securing the quality and appearance of a concrete structure because it can control the drying shrinkage cracks of the concrete structure to within a certain limit. In this study, with the purpose of commercializing ultra-low shrinkage concrete, the optimal amount of expansive agent and shrinkage reducing agent was determined through a lab test, and a concrete wall mock-up test was conducted to examine the shrinkage properties and crack control effects of ultra-low shrinkage concrete. As a result, it was confirmed that there was little drying shrinkage deformation in the wall specimen, and furthermore that no cracks were generated.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.647-650
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• 2005

This paper is to investigate the shrinkage properties of ultra high strength concrete(UHSC) incorporating $5\%$ of expansive additives(EA) along with $1\%$ of shrinkage reducing agent(SRA). UHSC subjected to steam curing and incorporated with steel fiber exhibited higher compressive strength than control UHSC by as much as50MPa at 7days, while at 28days, noticeable change in compressive strength was not observed between UHSC mixtures. Control UHSC subjected to steam curing had a $922{\times}10^6$ of autogenous shrinkage strain value, which was 6.7 times of drying shrinkage strain value at 42 days. The combination of EA and SRA resulted in a decrease in autogenous shrinkage by as much as half of control mixture. Steam curing contributed to the reduction of autogenous shrinkage by as much as $11\%$ compared with that of standard curing.

• International Journal of Control, Automation, and Systems
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• v.1 no.3
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• pp.390-394
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• 2003

To classify the significant wavelet coefficients into edge area and noise area, a morphological clustering filter applied to wavelet shrinkage is introduced. New methods for wavelet shrinkage using morphological clustering filter are used in noise removal, and the performance is evaluated under various noise conditions.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.441-444
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• 1999

The crack width of concrete structures subjected to shrinkage depend on a great number of parameters whose effects are restrain condition, the number and spacing of crack and the amounts of reinforcements. Through suitable reinforcement it is possible to make the individual cracks exceedigly small. This paper is to present the amount of reasonable reinforcement for crack control through a rational analysis of forces occuring in significantly restrained concrete structures due to the shrinkage. Also the analysis results from this paper are compared with the provisions for shrinkage and temperture reinforcement in the KCI concrete strucural design code.

• International Journal of Highway Engineering
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• v.6 no.2 s.20
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• pp.61-70
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• 2004

Cement treated Soil has superior characteristics as pavement-base including strength, curability, hardness, freezing resistance. However drying shrinkage of Cement treated base has been indicated as disadvantage, since reflection crack of surface layer is induced from drying shrinkage of cement treated base. This study propriety about low-shrinkage cement treated base that can control shrinkage of cement and control reflection crack at asphalt overlay & concrete slab.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.15-18
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• 2007

The purpose of this study is to suggest a reference for an extensive evaluation about effectiveness of four types of fibers to control plastic shrinkage crack of concrete. So in this study for the practical use in construction field, the plastic shrinkage cracks shown from four types of concrete reinforced by mixing four types of fibers are quantitatively evaluated in points of the workability and compressive strength. Test showed that the mixing of Cl, N, P fibers except for C2 fibers decreased fluidity of fresh concrete. Compressive strengths of four types specimens were similar. Plastic shrinkage cracks were reduced by mixing each fiber, especially C2 fibers was very effective to prevent the plastic shrinkage crack. Therefore the reinforced concrete mixed with C2 fibers exhibited superior mechanical performance than the others.