A series of reinforced G109 type specimens was fabricated and cyclically ponded with a15 w/o NaCl solution. The concrete mix design included cements of two equivalent alkalinities (0.32 and 1.08) and water cement ratio 0.50. Potential and macro-cell current between top and bottom bars were monitored as indicators of the onset of active corrosion. The specimens were subsequently autopsied, and the number and size of air voids along the top half of the upper rebar trace were counted, both at the corrosion site and where the steel remained passive. Also, chloride concentration was determined from powder samples taken from passive locations along the upper rebar trace. The observations and data indicated that both cement alkalinity and air voids aftected occurrence of active corrosion. The results are discussed within the context of better understanding factors that cause loss of passivity and active corrosion of steel in concrete.

In this research, the investigation of the temperature condition of reinforcing bars under laboratory temperature and outside temperature conditions in the insulation curing method of Korean-Chinese concrete bubble sheet to examine the suitability of the bubble sheet curing method. As a result, the heat of hydration of the concrete on the wall part affects the exposed reinforcing bars to delay the temperature drop at the part where the bubble sheet is not laid

In this research, the investigation of the temperature condition of reinforcing bars under laboratory temperature and outside temperature conditions in the insulation curing method of Korean-Chinese concrete bubble sheet to examine the suitability of the bubble sheet curing method. As a result, the heat of hydration of the concrete on the wall part affects the exposed reinforcing bars to delay the temperature drop at the part where the bubble sheet is not laid.

Steel pipe pile, which is used for the base of structures, need the reinforcing head method to prove enough dynamic performance. Currently there are various reinforcing head methods are used, but most of them have problems of structural complications and heavy charges. Thus, this study is to develop a reinforcing head method for steel pipe piles using hook type bending reinforcement, which can fix piles using nuts, and experimentally prove structural performances.

Recently corrugated steel member filled with concrete has been applied to various construction structures. In this study, the compressive strength was evaluated based on the number of bolt joints of corrugated steel. And compressive strength was also evaluated according to the shape and spacing of the steel rebar to improve the performance of the corrugated plates.

In this study, to evaluate the performance of the sleeve structure for high strength reinforced joints and to develop more economical and practical for high-strength reinforced joints sleeve.

We conducted this study to develope technique for removing fine mortar attached to waste reinforcing steel bar (D13). We observed the effect of the glycolic acid concentration (10 ~ 40%) and reaction time (0.5 ~ 4 hr) on the mortar removal. The reaction rate (−1.3089 hr−1) was the fastest at 20% of glycolic acid. The mortar was completely removed in 3 hrs. The reaction rate decreased with pH increase (1.4 ~ 2.0) at 20% of glycolic acid.

This study was performed to develop a reinforcing head method for steel pipe piles using screw type bending reinforcement, which can fix piles using nuts, and experimentally prove structural performances. In order to do so, steel pipe pile reinforcing head method test specimen using screw bending iron was produced and implemented to vertical tensile test, vertical compression test, and horizontal loading test. As a result, the test showed that it secured 1.28-3.62 times safety factors that are demanded from the design criteria for highway bridge.

최근 대구경철근에 적용할 수 있는 기계적 철근이음장치에 대한 연구가 진행되고 있다. 본 논문에서는 대구경 기계적 철근이음재에 대한 구조적 성능평가에 대하여 연구가 수행되었다. 원자력발전소에 대구경의 기계적 철근이음장치를 적용하기 위해서2가지 형태의 철근이음장치에 대한 실험이 수행되었으며, 원자력발전소에 적용되는 11번과 14번 및 18번에 대한 대구경 철근이음 장치가 조립되어 정적 및 동적실험이 수행되었다. 실험은 ASME SEC III DIV.2 CC-4330에 따라 이루어졌다.

본 연구에서는 SD500 고강도 철근에 적합한 강관 스플라이스 슬리브를 개발한 후에 실물크기의 20개 실험체를 제작하여 가력실험을 실시하였다. 그리고 강도를 비롯한 구조성능을 철근의 정착길이, 슬리브의 타입, 철근의 규격과 같은 실험변수에 따른 영향을 분석하고, 국내기준을 비롯한 주요기준에 따라서 비교, 평가하였다. 실험 결과는 SD500 고강도 철근용으로 개발된 강관 스플라이스 슬리브 철근이음은 주요기준에서 요구하는 구조성능을 가지고 있는 것으로 확인되었고 SD500 고강도 철근용 슬리브 철근이음에 대한 구조설계 기준 확립을 위한 기술적 자료를 제시하였다.