• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.119-123
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• 1995

This paper presents an accelerated-curing method by the war water method and discusses how these methods can be adapted for regular quality control and quality assurance of concret. Accelerated strength test data can be used for estimating the furture stength, e.g. the 28-day strength. An accelerated-curing method to predict the 28-day strength of concrete from 1-day warm water-cured test results was evaluated in the laboratory and the field. For these evaluations test are performed for 1845 standard specimens from 123 different batches of concrete. The results of this study the equation applicable universally with resonable accuracy are presented for estimating the potential strength of concrete by the warm water-curing method.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.301-307
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• 1997

This paper is evaluated for properties of aggregate and antiwashout admixture not only to minimize segregation and water contamination of underwater concrete but also to meet concrete quality required. Two antiwashout admixtures used in this study were available domestically and slump flow, pH, setting time, and filing property of fresh concrete and the compressive strength, flexural strength under water and in the air under 2 different curing conditions ($10^{\cire}C$ and $20^{\cire}C$ ) were measured. Compressive strength ratio of specimens cured in and water temperature $10^{\cire}C$ /$20^{\cire}C$ added HPEC and HPMC was 64% and 89%, respectively. Relative compressive strength of 2 kinds observed higher concrete added HPEC, 3% at $10^{\cire}C$ curing temperature, 34% at $20^{\cire}C$ . The flexural strength of specimens made under water was 1/4~1/6 of compressive strength similar to the existing data in the literature.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.87-93
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• 2018

The use of high-strength concrete in construction have been increasing steadily. However, high-strength concrete has a low water-binder ratio, and the problems such as cracks due to hydration heat and shrinkage during the hydration process at the early age. Recently, as a method to reduce the shrinkage of concrete, study of internal curing has carried out according to increasing about interest about it. In this study, the effect of compressive strength on the curing condition(drying, moist, water) was investigated by using artificial lightweight aggregate(LWA) in high strength and high volume mortar. As a result of autogenous shrinkage, the effect of shrinkage reduction was enhanced depending on the increasing of LWA replacement. According to the curing condition, the results of compressive strength showed the different trend. The compressive strength has increased on the drying and moisture condition and decreased on the water condition.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.99-107
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• 2014

In this study, the effects of curing procedures on the mechanical properties of recycled aggregate concrete (RAC) were investigated. The replacement ratios by recycled coarse aggregate were 0, 25, 50, 75 and 100% by mass of natural coarse aggregate. Steam curing was adopted to all recycled aggregate concrete mixtures. Compressive and split tensile strength, water porosity, chloride ions penetration resistance and drying shrinkage measurements were carried out to determine performance of the RACs. From the test results, it was found that the mechanical performance of RAC decreased as the recycled aggregate contents increased. Furthermore, steam curing reduced the compressive and split tensile strength, water porosity and total charge of RAC, especially at the early ages. However, at the later ages, the beneficial effect of steam curing was less prominent. This study clearly showed that initial steam curing could be one of practical methods to improve performance of RAC with higher replacement ratio of recycled aggregate.

• Textile Coloration and Finishing
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• v.17 no.6 s.85
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• pp.27-35
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• 2005

Conventional pad- dry-cure(thermo-fixation) process usually produces functional performance on both sides of a fabric. UV curing technique was applied to impart water- and oil-repellent finish effective only on the face of a PET knitted fabric. The preferential one-side coating, by virtue of the limited penetration of UV light, was achieved by W curing after padding of a fluorocarbon agent without special coating or printing equipments. The difference in the functional property of face and back sides was examined by measuring water and oil repellency at each side of the treated fabric. The influence of pre/post-irradiation dose and agent concentration on the performance of the finished fabrics were investigated. While increase in both resin concentration and post-irradiation did not have significant effect on the finish, UV pre-irradiation of PET fabrics caused remarkable influence presumably due to appropriate surface modification of PET fabrics required for facile wetting of the resin. The dimensional stability and color change of the UV cured fabrics measured by FAST and reflectance spectrophotometry showed significantly decreased color difference and increased percent extension compared with the samples pre-irradiated without agent application.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.115-116
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• 2016

This study applied BS replacement mortar's ERCO to see what impact it has on moisture evaporation and contraction changes, and resulted in the following. Depending on the rate of change in length according to the cure method of BS replacement mortar, high-strength areas were shown to have a bigger increase in the rate of change in length than regular or low-strength areas, and differences in rate of change in length due to ERCO cure methods were shown to be slight. For rate of changes in mass, on the whole there was an increase in the order of dry curing, cover curing, 7-day water curing, and28-day water curing. A comprehensive view says that after removal of test piece specimens, ERCO application did not expect a sufficient curing effect in the BS area.

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.25-34
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• 2000

When concrete is placed underwater, it is diluted with separating cementitious material and as a result the quality of concrete becomes poor. To solve this problem, antiwashout underwater concrete is increasingly used for the construction and repair of the concrete structure underwater. The objective of this study is to investigate the characteristics of antiwashout underwater concrete as to the mix proportion, casting and curing water through experimental researches. The unit weight of water and cement, water-cement ratio, fine aggregate ratio, unit weight of antiwashout underwater agent and superplasticizer, and casting and curing water were chosen to measure the suspended solids, pH, air contents, slump flow, unit weight of hardened concrete, and compressive strength. From this study, the incremental modulus at mix proportion design and unit weight of antiwashout underwater agent were increased more than fresh water, and it is a optimum mix proportion that the unit weight of water(and cement) is 230kg/$\textrm{m}^3$(460kg/$\textrm{m}^3$), waterOcement ratio is 50%, fine aggregate ratio is 40%, unit weight of antiwashout underwater agent is 1.2% of water contents per unit weight of concrete, and unit weight of supeplasticizer is 2.5% of cement contents per unit weight of concrete when the antiwashout underwater concrete is used for the underwater work of ocean.

• International Journal of Concrete Structures and Materials
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• v.4 no.1
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• pp.9-15
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• 2010

Silica fume is a common addition to high performance concrete mix designs. The use of silica fume in concrete leads to increased water demand. For this reason, Florida Department of Transportation (FDOT) allows only a 72-hour continuous moist cure process for concrete containing silica fume. Accelerated curing has been shown to be effective in producing high-performance characteristics at early ages in silica-fume concrete. However, the heat greatly increases the moisture loss from exposed surfaces, which may cause shrinkage problems. An experimental study was undertaken to determine the feasibility of steam curing of FDOT concrete with silica fume in order to reduce precast turnaround time. Various steam curing durations were utilized with full-scale precast prestressed pile specimens. The concrete compressive strength and shrinkage were determined for various durations of steam curing. Results indicate that steam cured silica fume concrete met all FDOT requirements for the 12, 18 and 24 hours of curing periods. No shrinkage cracking was observed in any samples up to one year age. It was recommended that FDOT allow the 12 hour steam curing for concrete with silica fume.

• Elastomers and Composites
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• v.33 no.2
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• pp.93-102
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• 1998

In electric cable industries, the curing extent of the rubber materials covering the electric cores gives an significant effect on their final performance. The curing extent of rubber is controlled mostly by pull-out velocity of cable in the extrusion process. The final curing extent may be different for different radial positions inside the rubber because of the non-uniform temperature distributions during the curing process. In this contribution, the prediction of curing extent distribution throughout the radial direction of rubber is represented when the cable is passing through the steam curing zone with a fixed pull-out velocity. The prediction of the optimum pull-out velocity for the desired curing extent distribution is also reported. The steady-state heat balance was developed for the curing and cooling processes in which the pull-out rubber was cured by high temperature steam and then cooled by ambient water. A few essential material properties such as density, specific heat, and thermal conductivity were measured to analyze the temperature distribution during the curing and cooling processes. The times to reach 90% curing extent at varying temperatures were measured and used to determine the final cure extent distribution inside the rubber.

• KCI Concrete Journal
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• v.12 no.1
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• pp.79-89
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• 2000

This research developed an accelerated curing processe for cellulose fiber reinforced cement composites using vigorous reaction between carbon dioxide and cement paste. A wet-processed cellulose fiber reinforced cement system was considered. Carbonation curing was used to complement conventional accelerated curing. The parametric study followed by optimization investigation indicated that the carbonation curing can enhance the productivity and energy efficiency of manufacturing cellulose fiber reinforced cement composites. This also adds environmental benefits to the technical and economical advantages of the technology.