• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.715-720
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• 2003

The chief factors for the penetration and diffusion of chloride ions in concrete are water-cement ratio(W/C), aging, curing conditions, chloride ions concentration of given environment., wet and dry conditions and etc. In this study, of these factors effect of curing conditions such as standard and outdoor curing on the characteristics of chloride ions diffusion in concrete were researched when environmental factors for the penetration and diffusion of chloride ions were constant. For this purpose, the voltages passing through the diffusion cell were measured by using accelerated test method using potential difference, and then diffusion coefficients of chloride ions by using Andrade's method were estimated for 44%, 49.5% and 60% of w/c, respectively. As a result., according to curing conditions correlation among diffusion coefficients of chloride ions, W/C and aging were concluded through multiple regression model.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.105-114
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• 2010

The objective of the paper is to experimentally investigate the compressive strength of the concrete incorporating fly ash. Ordinary Portland cement(OPC). Water to binder ratio(W/B) ranging from 30% to 60% and curing temperature ranging from $-10^{\circ}{\sim}65^{\circ}C$ were also adopted for experimental parameters. Fly ash was replaced by 30% of cement contents. According to the results, strength development of concrete contained with fly ash is lower than that of plain concrete in low temperature at early age and maturity. In high curing temperature, the concrete with fly ash has higher strength development than that of low temperature regardless of the elapse of age and maturity. Fly ash can have much effect on the strength development of concrete at the condition of mass concrete, hot weather concreting and the concrete products for the steam curing.

• Journal of the Korea Institute of Building Construction
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• v.9 no.6
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• pp.113-119
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• 2009

This study is to investigate the fundamental and fireproof qualities of high strength concrete corresponding to changes in the curing factors and the PP fiber ratio. The results were as follows. For the fundamental characteristics of concrete, the fluidity was reduced in proportion to the increase in the PP fiber ratio. The compressive strength was somewhat reduced according to an increase in the PP fiber ratio. However, it had the high strength scope of more than 60 MPa at 7 days and of more than 90 MPa at 28 days. On the spalling mechanism followed by changes of the water content ratio, spalling was prevented in all combinations, except the specimen without PP fiber and subjected to 3.0% of moisture contents. When spalling was prevented at that time, the residual compressive strength ratio was 22%~41% and the mass reduction ratio was 5%~7%, which was relatively favorable. As the spalling mechanism corresponds to changes in the curing method, spalling was prevented in concrete with a PP fiber mixing ratio of more than 0.05% in the event of standard curing, and in concrete with a PP fiber mixing ratio of more than 0.10% in the case of steam curing and autoclave curing. In these cases, when spalling was prevented, the residual compressive strength ratio was 23~42% and the mass reduction ratio was 7~11%. In these results, the ease of spalling prevention in high strength concrete was inversely proportional to the water content ratio. Depending on the curing method, spalling was prevented in concrete with over 0.05% PP fiber with standard curing and in concrete with over 0.1% PP fiber with steam curing and autoclave curing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.25-28
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• 2005

This study investigates the field application of surface insulation curing method, which combined double layer bubble sheet(DBS) and thick-curing-material(TCM) for cold weather concreting. According to the test, deck slab, curing only upper section with DBS and TCM, does not make big different temperature history with that, curing both upper and bottom section during daily average temperature 6.5t. It is concluded that combination of DBS and TCM in only upper section can be safely cured in early period of time during cold water concreting. The field test was carried out with this favourable data. The upper deck slab was insulated by combination of DBS and TCM, and the construction was surrounded by tent. in order to protect from outside wind. The test result shows that the lowest temperature of deck slab indicated 6$ ^{circ}C $. It demonstrated that this curing method can resist early frost and save construction cost in the side of management and saving labor cost, compared with previous method. In addition, the column specimen, combined both form and bubble board, exhibited favorable temperature history, due to internal hydration heat insulation effect.

• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.387-392
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• 2001

When cavity floor is near the pulp, polymerization of light-activated restorations results in temperature increase. This temperature increase cause by both the exothermic reaction process and the energy absorbed during irradiation. Therefore instating base is required. Most frequently used insulating base is glass ionmer. The purpose of this study was to evaluate intrapulpal temperature changes of glass ionomer according to various curing intensity and curing time. Caries and restoration-free mandibular molars extracted within three months were prepared Class I cavity of 3$\times$6mm with high speed handpiece. 1mm depth of dentin was evaluated with micrometer in mesial and distal pulp horns. Pulp chambers were filled with 37.0$\pm$0.1$^{\circ}C$ water to CEJ. Chromium-alumina thermocouple was placed in pulp horn for evaluating of temperature changes. glass ionomer material was placed in 2mm. total curing time was 40s: continuous 40s, intermittent 20s, intermittent 10s. Glass ionomer material was cured with 300mW/$\textrm{cm}^2$, 550mW/$\textrm{cm}^2$ light curing unit. The results were as follows : 1. Temperature in pulp increased as curing unit power is increased. 2. Temperature in pulp more increased continuous emission than intermittent emission.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.260-267
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• 2021

The purpose of this study was to experimentally investigate the effects of curing methods on the compressive strength and tensile behavior of alkali-activated slag-based fiber-reinforced composite with a water-to-binder ratio of 15%. Three kinds of mixtures according to the curing conditions were prepared and compressive strength and tension tests were performed. Test results showed that the compressive strength and the first cracking strength of composites decreased when high temperature curing and air curing were adopted, while tensile strain capacity of composites increased. It was also observed that crack spacing and crack width of composites decreased by applying high temperature and air curing.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.04a
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• pp.135-137
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• 2008

PVA films with 1,2,3,4-Butanetetracarboxylic acid(BTCA) and sodium hypophosphite monohydrate(SHM) were crosslinked via thermal curing. Different parameters affecting on the crosslinking were investigated including BTCA and SHM concentration, curing temperature and time. The cured films was extracted with boiling water and gel fraction was calculated from weight change of the PVA films. Moisture regain of the gelled films was also measured. While the gel fraction of PVA films increased with increasing curing temperature and time, moisture regain decreased. Water resistance of the crosslinked PVA films improved by the BTCA crosslinking treatment.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.395-398
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• 2003

This study is performed to evaluate the engineering properties of cement mortar with hwangtoh and fly ash The absorption ratio is in the range of $5.22{\sim}13.16%\;and\;8.53{\sim}13.29%$ at the curing age 14 and 28 days, respectively. The compressive strength is in the range of $92{\sim}458kgf/cm^2\;and\;88{\sim}316kgf/cm^2$ in water and dry cruing at the curing age 28days, respectively. The bending strength and dynamic modulus of elasticity are shown in similar tendency in water and dry curing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.2
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• pp.137-146
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• 2001

The non-destructive tests are widely used to predict the strength of existing structures. The purpose of the present study is to propose the prediction equations for strength evaluation of concrete structures. The present study focuses on the rebound method and ultrasonic pulse velocity method for quartzite aggregate concrete. The major test variables include the water-cement ratio and curing methods. The water-cement ratio are 0.4, 0.5, 0.6, 0.7, respectively and the curing method covers ail-dry condition and standard curing condition. The prediction equations for strength of concrete are proposed from the present test data.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.46-51
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• 2004

The surface layer in dredged and reclaimed marine clay is improved by mixing of shallow soils and hardening agents, which is made of cement, containing some other special admixtures. Tests in both laboratory and field settings are performed to investigate the improvement effect and strength properties of cement-stabilized soils. The test results show that the hardening agent sufficiently improves the soil properties of the surface layer, while increasing the load-carrying capacity. The strength of cement-stabilized soils depends, primarily, on water-to-cement ratio and curing temperature. That is, the higher curing temperature and the longer curing time, the higher the strength in cement-stabilized soils. The high ratio of water-ta-cement results in a lower strength.