• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2012.11a
• /
• pp.27-28
• /
• 2012

This study is to low-temperature in using self-adhesive waterproofing sheet. Using self-adhesive waterproofing sheet is very comfortable in a waterproofing construction site. However, when self-adhesive waterproofing sheet is constructed from a low-temperature environment, there has been a attachment strength shortage. Therefore, this study on the attachment strength of self-adhesive waterproofing sheet is to investigate the low-temperature in the environment.

• Computers and Concrete
• /
• v.28 no.5
• /
• pp.451-463
• /
• 2021

Inorganic basalt fiber (BF) is a novel sort of commercial concrete fiber which is made with basalt rocks. Previous studies have not sufficiently handled the behavior of self-compacted concrete, at elevated temperature, containing basalt fiber. Present endeavor covers experimental work to examine the characteristics of this material at high temperature considering different fiber content and applied temperature. Different tests were carried out to measure the mechanical properties such as compressive strength (fc), modulus of elasticity (E), Poisson's ratio, splitting tensile strength (fsplit), flexural strength (fflex), and slant shear strength (fslant) of HSC and hybrid concrete. Gene expression programming (GEP) was employed to propose new constitutive relationships depending on experimental data. It was noticed from the testing records that there is no remarkable effect of BF on the Poisson's ratio and modulus of elasticity of self-compacted concrete. The flexural strength of basalt fiber self-compacted concrete was not sensitive to temperature in comparison to other mechanical properties of concrete. Fiber volume fraction of 0.25% was found to be the optimum to some extend according to degradation of strength. The proposed GEP models were in good matching with the experimental results.

• The Journal of Advanced Prosthodontics
• /
• v.5 no.3
• /
• pp.305-311
• /
• 2013

PURPOSE. Over the past years, the adhesion of fiber posts luted with simplified adhesive systems has been a matter of great interest. The aim of this study was to assess the post retentive potential of a self-adhesive resin cement using different adhesive systems to compare the push-out bond strengths of fiber posts. MATERIALS AND METHODS. The post spaces of 56 mandibular premolar roots were prepared and divided into 4 experimental groups and further divided into 2 subgroups according to testing time (n=7). The fiber posts (Rely X Fiber Post) were luted with a self-adhesive resin cement (RelyX Unicem) and one of the following adhesive systems: no adhesive, a total-etch adhesive resin (Single Bond), a two-step self-etch adhesive resin (Clearfil SE Bond) and a one-step self-etch adhesive resin (Clearfil S3 Bond). Each root was cut horizontally, and 1.5 mm thick six root segments were prepared. Push-out tests were performed after one week or three months (0.5 mm/min). Statistical analysis were performed with three-way ANOVA (${\alpha}$=.05). RESULTS. Cervical root segments showed higher bond strength values than middle segments. Adhesive application increased the bond strength. For one week group, the total-etch adhesive resin Single Bond showed higher bond strength than the self-adhesive resin cement RelyX Unicem applied without adhesive resin at middle region. For 3 months group, the two-step self-etch adhesive resin Clearfil SE Bond showed the highest bond strength for both regions. Regarding the time considered, Clearfil SE Bond 3 months group showed higher bond strength values than one week group. CONCLUSION. Using the adhesive resins in combination with the self-adhesive resin cement improves the bond strengths. The bond strength values of two-step self-etch adhesive resin Clearfil SE Bond improved as time passes.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.50 no.4
• /
• pp.434-442
• /
• 2023

This study was aimed to evaluate the bonding performance of a self-adhesive giomer and compare it to a conventional flowable composite resin with regard to shear bond strength and microleakage in enamel and dentin. Healthy human premolars extracted for orthodontic treatments were used in the study. For shear bond strength tests, enamel and dentin specimens were prepared for the study group with self-adhesive giomer and for the control group with conventional flowable composite resin with a 5th-generation adhesive system. A universal testing machine was used to measure the shear bond strength. For the microleakage tests, specimens were immersed in a 2% methylene blue solution for 24 hours, cut into sections, and evaluated with a stereomicroscope for the extent of dye penetration. The results of the study showed no statistically significant difference in shear bond strength between the self-adhesive giomer and the conventional flowable composite resin in enamel (p = 0.091). On the contrary, in dentin, the self-adhesive giomer showed significantly lower shear bond strength (p < 0.0001). The microleakage of the self-adhesive giomer was significantly higher than that of the conventional flowable composite resin (p = 0.002). Self-adhesive giomer is considered useful for restoring small cavities at the enamel level of pediatric patients by reducing chair time with the advantage of a simple bonding process. However, as the study was conducted in a laboratory setting, further research in a clinical environment is deemed necessary.

• Restorative Dentistry and Endodontics
• /
• v.29 no.4
• /
• pp.353-364
• /
• 2004

The purpose of this study was to compare and to evaluate the combination use of 5 kinds of dentin adhesive systems and 5 kinds of composite resins using micro-shear bond test. Five adhesive systems (Prime & Bond NT (PBN). Onecoat bond (OC), Excite (EX), Syntac (SY), Clearfil SE bond (CS)) and five composite resins (Spectrum (SP), Synergy Compact (SC), Tetric Ceram (TC), Clearfil AP-X (CA), Z100 (Z1)) were used for this study ($5{\;}{\times}{\;}5{\;}={\;}25group$, n =14/group). The slices of horizontally sectioned human tooth were bonded with each bonding system and each composite resin, and tested by a micro-shear bond strength test. These results were analyzed statistically. The mean micro-shear bond strength of dentin adhesive systems were in order of CS (22.642 MPa), SY (18.368 MPa), EX (14.599 MPa). OC (13.702 MPa). PBN (12.762 MPa). The mean bond strength of self-etching primer system group (CS, SY) in dentin was higher than that of self-priming adhesive system groups (PBN, EX, OC) significantly (P<0.05). The mean bond strength of composite resins was in order of SP (19.008 MPa), CA (17.532 MPa). SC (15.787 MPa), TC (15.068 MPa). Z1 (14.678 MPa). Micro-shear bond strength of SP was stronger than those of other composite resins significantly (P < 0.05). And those of TC and Z1 were weaker than other composite resins significantly (P < 0.05). No difference was found in micro-shear bond strength of composite resin in self-etching primer adhesive system groups (CS, SY) statistically. However, there was significant difference of micro-shear bond strength of composite resin groups in self-priming adhesive systems group (PBN, EX, OC). The combination of composite resin and dentin adhesive system recommended by manufacturer did not represent positive correlation. It didn't seem to be a significant factor.

• Restorative Dentistry and Endodontics
• /
• v.40 no.1
• /
• pp.68-74
• /
• 2015

Objectives: This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. Materials and Methods: Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. Results: In GB, XV and SE ($pH{\leq}2$), the bond strength was decreased significantly when the dentin was etched (p < 0.05). In BB, AE and SU (pH 2.4 - 2.7), additional etching did not affect the bond strength (p > 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p < 0.05). When adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. Conclusions: The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.11a
• /
• pp.252-253
• /
• 2021

In this study, butyl rubber, which is the main material constituting the self-adhesive butyl rubber waterproofing sheet, was mixed with reclaimed rubber, and tensile strength, tear strength, peeling resistance strength, and adhesion strength were measured for sample prepared by mixing ratio. As a result, it was confirmed that peeling resistance strength and adhesion strength decreased as the reclaimed rubber content increased, and tensile strength and tear strength did not change significantly.

• International Journal of Internet, Broadcasting and Communication
• /
• v.15 no.4
• /
• pp.294-303
• /
• 2023

This study was to find out the differences in self-esteem, body composition, and muscle strength of middle-aged women, and nine physical labor groups were selected as beautification workers at D University in Cheonan, and a total of 17 were selected as non-physical labor groups were 8 full-time housewives living in Cheonan. After selecting the subjects, the subjects arrived 30 minutes before the start of the experiment and completed the self-esteem questionnaire. After taking the stability, the measurement was carried out in the order of body composition, grip strength, and isokinetic muscle function, and the independent sample t-test was conducted. First, middle-aged women's self-esteem according to the type of physical labor was high in the physical labor group in relation to others among the sub-factors. Second, there was no significant difference in body composition according to the physical labor patterns of middle-aged women. Third, there was no significant difference in lower limb isokinetic muscular strength according to the types of physical labor of middle-aged women. Third, there was no significant difference in lower limb isokinetic muscular strength according to the types of physical labor of middle-aged women. The self-esteem according to physical labor is caused by the sense of belonging in the workplace, and the difference between body composition and muscular strength is insignificant. Therefore, it is necessary to introduce a physical activity program to promote self-esteem due to aging and prevent physical deterioration regardless of occupation.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2023.05a
• /
• pp.321-322
• /
• 2023

This study compared the compressive strength and healing strength to confirm the self-healing performance of mortar incorporating Bioinspired Self-healing Capsule (BSC) into cement composites as part of a study to mitigate the problem of durability deterioration due to cracks in concrete structures. As a result of the evaluation, it was found that the healing performance decreased as the mixing ratio of the BSC capsule increased.

• Journal of the Korean Ceramic Society
• /
• v.13 no.1
• /
• pp.20-24
• /
• 1976

These are many kinds of self-hardening methods for sand mold using sodium silicate. When sodium silicate solution is mixed with calcium-orthosilicate powder hardening reaction occurs, which is based for self-hardening method at high temperature. The high temperature strength and resicual strength of mold are related to the mole ratio of sodium silicate and the contents of calcium-orthosilicate powder. The results obtained in this study were as follows: 1) The high temperature strength of mold was maximum at about $600^{\circ}C$, and at higher temperature showed lower value on the contrary. 2) The high temperature strength of mold was increased by increasing the amount of sodium silicate having lower mole ratio and high concentration. 3) The residual strength of mold was reduced by increasing the mole ratio of sodium silicate and increasing the concentration of calcium-orthosilicate.