• Computers and Concrete
• /
• v.24 no.3
• /
• pp.249-258
• /
• 2019

In order to investigate the strength recovery of fire-damaged concrete after post-fire curing, concrete specimens were heating at $2^{\circ}C/min$ or $5^{\circ}C/min$ to 400, 600 and $800^{\circ}C$, and these exposed specimens were soaked in the water for 24 hours and following by 29-day post-fire curing. The compressive strength and split tensile strength of the high-temperature-exposed specimens before and after post-fire curing were tested. The proportion of split aggregate in the split surfaces was analyzed to evaluate the mortar-aggregate interfacial strength. After the post-fire curing process, the split tensile strength of specimens exposed to all temperatures was recovered significantly, while the recovery of compressive strength was only obvious within the specimens exposed to $600^{\circ}C$. The tensile strength is more sensitive to the mortar-aggregate interfacial cracks, which caused that the split tensile strength decreased more after high-temperature exposure and recovery more after post-fire curing than the compressive strength. The mortar-aggregate interfacial strength also showed remarkable recovery after post-fire curing, and it contributed to the recovery of split tensile strength.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.170-173
• /
• 2006

The purpose of this study is to investigate the effect of post-fire-curing on the strength recovery of fire-damaged concrete The 170 specimens have been tested with variables of concrete strengths(20, 30, 40, 50, 60Mpa) exposed to elevated temperatures till $600^{\circ}C$ and $800^{\circ}C$. After natural cooling, the specimens were subjected to post-fire-curing in water and in a controlled chamber for a total duration of 56days. Unstressed compressive strength was conducted to examine the change in the concrete. The test results indicated that the post-fire-curing results in substantial strength recovery and its extent depend on the method and duration of recuring.

• Textile Coloration and Finishing
• /
• v.14 no.1
• /
• pp.43-50
• /
• 2002

Silk/Cotton fabrics were treated with butanetetracarboxylic acid(BTCA) to improve crease recovery and anti-shrinking properties at various curing temperatures and pH values. We investigated the effects of finishing conditions on add-on of BTCA, bending property(E, 2HB), wrinkle recovery angle, shrinkage, and dyeing properties. The Add-on of BTCA increased with increasing curing temperature and concentration. Crease recovery was improved with decreasing shrinkage. Maximum add-on of BTCA was showed at pH 2.5. In case of dyeing and mercerization, silk side treated with BTCA was more flexible than untreated, whereas cotton side was more stiff. In dyeing after mercerization, B and 2HB values were higher and K/S values were doubled nearly. The hand of fabric improved with decreasing B and 2HB by the BTCA treatment. BTCA treatment after reactive dyeing improved crease recovery, and caused no change of color difference. However, BTCA treatment after reactive dyeing didn't improve crease recovery, whereas B and 2HB were decreased considerably by the treatment.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.05a
• /
• pp.103-104
• /
• 2019

The aim of the research is assessing the possibility of recovering the compressive strength of the mortar mixture replaced excessively high volume of blast furnace slag accidently. As a result of the experiment, in the case of compressive strength, painting sodium oxide showed higher compressive strength recovery effect than painting calcium oxide. As a curing temperature, 20℃ showed advanced result rather than 65℃. From the wet curing, the reaction was confirmed, deeper penetration depth was checked at 20℃ than 60℃ temperature. Therefore for the concrete mixture with excessively high volume of blast furnace slag, it is considered that painting sodium hydroxide and curing 20℃ can recover the compressive strength effectively.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.05a
• /
• pp.199-200
• /
• 2019

The purpose of the research is assessing the possibility of strength recovery for mortar added with accidently high amount of fly ash. For compressive strength at 28 day, the sample painted with sodium hydroxide showed higher compressive strength than the sample painted with calcium hydroxide. Regarding the curing conditions, the curing temperature 65℃ provided better conditions than the curing temperature 20℃ in aspect of solution penetration depth and reactivity of fly ash. In the case of drying after saturation, the case painted with sodium hydroxid 65℃ showed the clearest engrossing mark.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.22 no.4
• /
• pp.525-534
• /
• 1998

Cotton fabrics were finished with mixture of BTCA(1,2,3,4,-butanetetracarboxylic acid) and polyalkyleneoxide-modified amino-functional silicone by pad-dry-cure process to achieve better DP performance with a higher retention of physical properties as compared to those of finished with BTCA alone. The results indicated that BTCA improved the wrinkle recovery but reduced significantly the tensile and tear strength of the treated fabrics. Whereas silicone imparted a lower wrinkle recovery, a lower loss of tensile strength than BTCA, in addition improved considerably the tear strength owing to reduction in inter-fiber and/or inter-yarn frictional forces. The concentration and curing temperature needed to enhance physical properties were as follows; for BTCA treatments 6%, at 18$0^{\circ}C$, for silicone treatments 1% at 14$0^{\circ}C$. This optimum concentration of silicone was observed by using the mixture of BTCA and silicone. The wrinkle recovery and DP rating of cotton fabrics treated with mixture of 4% BTCA and 1% silicone at a curing temperature of 17$0^{\circ}C$ was similar to those of treated with 6% BTCA at a curing temperature of 18$0^{\circ}C$, and other performance properties observed were; an increase in tensile strength, extension, toughness, abrasion resistance and moisture regain due to the reduction of BTCA concentration and curing temperature, futhermore an improvement in bending and surface properties due to the lubricating effect of silicone. On the other hand 1% aqueous silicone solution showed the lowest surface tension. Such nonionic surface activity resulted in a more uniform and rapid deposition of BTCA on the fiber or fabric.

• Textile Coloration and Finishing
• /
• v.14 no.3
• /
• pp.19-25
• /
• 2002

Silk/cotton fabrics were treated with butanetetracarboxylic acid(BTCA) under various treating conditions such as concentration, treated time and curing temperatures. Bending property, tensile strength, wrinkle recovery angle, and shrinkage were measured. The BTCA concentration in the saponfication mixture was measured by an isocratic HPLC equipped with the strong cationic exchange column Aminex HPX-87-H and a UV detector. The detected concentration of BTCA was shown in silk side much more than that of cotton side. The bending and shrinkage properties were improved at minimum curing condition and the lower concentration of BTCA. Tensile strength decreased with increasing concentration of BTCA, curing temperature and treated time, while wrinkle recovery angle increased.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2019.11a
• /
• pp.73-74
• /
• 2019

In order to examine the chemical stabilization through DCG curing of cement paste exposed to high temperature environment, we produced a sample of 40% W/C cement paste and heated it for 180 minutes under the heating temperature of $800^{\circ}C$. The DCG curing time was 6, Three time conditions were divided into 12 and 18 hours. As a result of XRD analysis, Calcite ($CaCO_3$) was found in Theta 29.4, 40, and 46.5o. As the curing time increased, the peak of Calcite also increased, which is due to the increased reaction time with DCG. Therefore, Calcite produced through DCG curing seems to have stabilized chemically by filling the pores generated by heating.

• Journal of Environmental Science International
• /
• v.27 no.11
• /
• pp.1023-1028
• /
• 2018

Shape memory materials are widely used in high-tech industries. Although shape memory polymers have been developed, they have a disadvantage, only unidirectional resilience. Shape memory polymers with bi-directional recovery resilience have been actively studied. In this study, a bidirectional shape memory polyurethane was synthesized using poly(${\varepsilon}$-caprolactone) diol, methylene dicyclohexyl diisocyanate, and hydroxyethyl acrylate. The first physical curing occurred between hard segments and hydrogen bondings when the solution was dried. The second curing in acrylate groups was performed by UV exposure. A degree of curing was analyzed by infrared spectroscopy. The shape memory properties of 2 step-cured polyurethanes were investigated as a function of UV curing time.

• Textile Coloration and Finishing
• /
• v.4 no.3
• /
• pp.122-130
• /
• 1992

To improve the physical properties and the dyeing properties of silk, the silk fabric was treated with urea resin and reactive dyeing. The effects of urea resin concentration, pH of padding bath and curing condition were investigated in order to find optimum condition and the following results are obtained The optimum condition for the crease recovery of silk fabric was urea resin concentration of 80 g/ι, pH of 7, the curings temperature of about 135$^{\circ}C$, and the curing time of 3 minutes. The crease recovery and the thermal insulation ratio of silk fabric were increased by the above treatment. K/S increased as the adding amount of Na$_2$SO$_4$ increased, K/S, however was not affected by the adding amount of Na$_2$CO$_3$. Co1or fastness of the dyed fabrics treated with urea resin were improved slightly compared with untreated ones.