PURPOSES : The objective of this study is to evaluate the curing and adhesive behavior of asphalt emulsions including polymer-modified emulsions for chip seals and fog seals. METHODS : For the laboratory testing, the evaporation test, the bitumen bond strength (BBS) test, and the Vialit test are used. Also, the rolling ball test and the damping test are employed to evaluate the curing properties of the fog seal emulsions. In order to conduct all the tests in controled condition, all test procedures are performed in the environmental chamber. The CRS-2L and the SBS CRS-2P emulsions are used as a polymer-modified emulsion, and then unmodified emulsion, the CRS-2, is compared for the evaluation of chip seal performance. For the fog seal performance evaluation, two types of polymer-modified emulsions (FPME-1 and FPME-2) and one of unmodified emulsion, the CSS-1H, are employed. All the tests are performed at different curing times and temperatures. RESULTS AND CONCLUSIONS : Overall, PMEs show better curing and adhesive behavior than non-PMEs regardless of treatments types. Especially, the curing and adhesive behavior of PMEs is much better than non-PMEs before 120 minutes of curing time. Since all the test results indicate that after 120 minutes of curing time the curing adhesive behavior of emulsions, the early curing time, i.e., 120 minutes, plays an important role in the performance of chip seals and fog seals.

The influence of adding urea to phenol-formaldehyde (PF) resins as a co-polymer component were investigated aiming at synthesizing useful phenol-urea-formaldehyde resins. Urea was added at 10% by total resin weight. Several methods for the addition of urea to the PF resins during synthesizing resins to see the co-polymerization occurs between urea and PF resins. The urea was added at the beginning, at three different middle stages, and at the end of PF resin synthesis. The copolymerized methylene bridges between phenol and urea molecules were not observed by 13C-NMR; no signal around 50ppm. The curing of urea-modified PF resins, evaluated by dynamic mechanical analysis(DMA), showed some differences among the resins. DMA gel times ranged from 2.75 min to 3.25 min and the resins made with earlier urea additions showed slightly shorter gel times. The longest cure time and gelation time was observed for the resin PFU. Catalyst effects on the DMA cure time values of resins were not significant with different amounts of catalyst or different types of catalyst for all resins tested. Gel times of urea-modified PF resins shortened the most by triacetin catalyst

Acrylic resin(ACR) was blended with a curing agent, hexamethoxymethylmela-mine(HMMM), in which blending ratio was 70:30. The curing behavior was examined using Rheovibron. Cross-linking reaction started at 170℃ in 2 min of reaction and curing was completed in 10 min. It was found that the extent of cross-linking increased with the content of acetoacetoxyethyl methacrylate monomer in the ACR.

Curing reaction was carried out with the acrylic resin (ACR) [n-butyl acrylate/atyrene/2-hydroxyethyl methacrylate/acetoacetoxyethyl methacrylate (AAEM)] synthesized before and a curing agent, hexamethoxymethylmelamine (HMMM). With rotational rheometer, the effect of catalysts on curing rate of acrylic resin/melamine was examined. Among the four catalysts used, p-toluene sulfonic acid showed the highest reactivity, and the optimum amount of catalyst was 0.5 phr. It was observed that in the ACR/HMMM curing reaction, gelation point was lowered with the increasing the amount of AAEM and HMMM in the ACR.

Two-packaged polyurethane coatings were prepared by blending benzoic acid lactone modified polyester polyol(BLMPs) and HDI-biuret. BLMPs were synthesized by polycondensation of benzoic acid, viscosity depression component, with 1,4-butanediol, adipic acid, and polycaprolactone polyol. Kinematic viscosity of BLMP was gradually decreased with increasing benzoic acid content in BLMP. The low viscosity of modified polyester has an advantage of making a high-solid content coatings. After the film was coated with the prepared polyurethane coatings and cured at room temperature, the various physical properties were measured. They showed good physical properties such as flexibility, impact resistance, cross hatch adhesion, yellowness index, and rust resistance. These advantages are the results of introducing polycaprolactone polyol.

본 연구에서는 양생조건이 다른 압축강도 90 MPa 수준의 고강도 콘크리트 부재의 휨거동 실험을 수행하였다. 실험변수는 정상 및 저온 양생 조건, 인장 철근량 및 콘크리트 압축강도 수준 등을 고려하였다. 8개의 보 부재를 제작하여 휨 실험을 수행하였으며 균열 간격, 하중-처짐 관계, 하중-변형률 관계 및 연성지수를 파악하였다. 실험결과는 철근량이 증가함에 따라 균열 개수는 증가하고 균열간격은 감소하는 경향 을 나타내며, 콘크리트 강도가 높을수록 균열개수가 줄어들기는 하지만 그 효과는 철근량보다는 상당히 작은 것을 알 수 있었다. 설계기준에서 제안된 평균 균열 간격 식과 비교한 결과, 실험결과가 제안식의 결과보다 약간 크게 나타났으나, 제안식은 콘크리트 강도 및 양생조건을 반영 하지 못하는 문제점이 있다. 정상 양생된 부재들의 연성지수는 3.36~6.74이며, 저온 양생된 부재들의 연성지수는 1.51~2.82으로 나타나, 저온 양생된 부재들의 거동은 정상 양생된 부재들에 비해서 연성도지수가 저감됨을 확인하였으며, 본 연구와 기존 연구의 연성지수를 비교한 결과, 고강도 콘크리트 부재의 연성지수는 선행연구의 보통강도 콘크리트의 연성지수 보다 크게 나타났으나, 더 구체적인 결과를 파악하기 위해서 는 추가연구가 필요하다고 판단된다.

This study was carried out to evaluate effects of curing method and age on compressive behavior of steel fiber reinforced Alkali-Activated Slag(AAS) concrete. AAS and Steel Fiber Reinforced Concrete (SFRC) material with specific compressive strength of 30MPa was reinforced with 0% to 1% steel fibers at the volume fraction. Two types of curing methods were used: water curing and exposed curing. Curing time is 3, 7, 28 day. Experimental results indicated that compressive strength, elastic modulus, compression index.