To cope with automobile exhaust gas regulations, ISG (Idling Stop & Go) and charging control systems are applied to HEVs (Hybrid Electric Vehicle) for the purpose of improving fuel economy. These systems require quick charge/discharge performance at high current. To satisfy this characteristic, improvement of the positive electrode plate is studied to improve the charge/discharge process and performance of AGM(Absorbent Glass Mat) lead-acid batteries applied to ISG automotive systems. The bonding between grid and A.M (Active Material) can be improved by applying the Sand-Blasting method to provide roughness to the surface of the positive grid. When the Sand-Blasting method is applied with conditions of ball speed 1,000 rpm and conveyor speed 5 M/min, ideal bonding is achieved between grid and A.M. The positive plate of each condition is applied to the AGM LAB (Absorbent Glass Mat Lead Acid Battery); then, the performance and ISG life characteristics are tested by the vehicle battery test method. In CCA, which evaluates the starting performance at -18 oC and 30 oC with high current, the advanced AGM LAB improves about 25 %. At 0 oC CA (Charge Acceptance), the initial charging current of the advanced AGM LAB increases about 25 %. Improving the bonding between the grid and A.M. by roughening the grid surface improves the flow of current and lowers the resistance, which is considered to have a significant effect on the high current charging/discharging area. In a Standard of Battery Association of Japan (SBA) S0101 test, after 300 A discharge, the voltage of the advanced AGM LAB with the Sand-Blasting method grid was 0.059 V higher than that of untreated grid. As the cycle progresses, the gap widens to 0.13 V at the point of 10,800 cycles. As the bonding between grid and A.M. increases through the Sand Blasting method, the slope of the discharge voltage declines gradually as the cycle progresses, showing excellent battery life characteristics. It is believed that system will exhibit excellent characteristics in the vehicle environment of the ISG system, in which charge/discharge occurs over a short time.

In this study, an experimental study was carried out to evaluate the bond shear performance according to the shear connector between the glue-laminated timber and steel interface. Ten block shear specimens were fabricated according to the configuration of the adhesive surface of wood and steel. In addition, four test specimens were produced according to the main variable shape of the wood-concrete shear connector. As a result of the block shear test, the shear strength of the steel-wood adhesive is shown to have a shear performance greater than the wood-wood shear strength. As a result of the push-out test according to the shape of the shear connector, the shear strength increased linearly with the attachment area. The complete composite behavior between the glued-laminated timber and the steel can be secured.

국내 고속도로는 아래 fig 1.(left)과 같이 1970년 개통한 경부고속도로를 시작으로 2010년대에 접어들면서 전국에 도로 네트워크를 구성하였다. 최근 노후화된 포장의 증가로 도로 포장 유지관리에 대한 필요성이 증가하고 있으며, fig 1.(right)는 보수 기법으로 아스팔트 덧씌우기의 비율이 약 62%로 지배적인 것을 보여준다. 하지만, 아스팔트 덧씌우기 또는 복합 포장의 부착 상태가 불량할 경우 포장 수명의 최대 80%까지 감소된다는 연구결과가 보고되었음에도(Khweir and Fordyce, 2003), 국내에서는 명확한 평가 기준이 마련되어 있지 않다. 따라서, 본 연구는 기존 콘크리트 포장 위 아스팔트 덧씌우기의 부착 저항성 평가 방법에 대한 기준을 제시하고, 온도와 표면 거칠기에 따른 부착 거동 특성을 정의하였다. 실험 방법으로는 부착 파손의 결정적인 전단 모드에 대하여 평가하였으며, 장비는 Direct Shear Tester를 이용하여 평가하였으며, 실험의 반복성을 향상시키기 위해 포장 거칠기 모사 시편을 제작하여 평가하였다. 평가 결과 온도와 표면 거칠기에 따라 영향을 받는 것을 확인하였으며, 높은 온도에서 낮은 최대 전단강도를 보였고, 표면 거칠기에 따라서는 MTD가 가장 높은 6mm Tinning이 아닌 Undersealing 표면에서 가장 높은 최대 전단강도를 나타내었다. 다음 fig 2.는 다양한 온도에서 표면 거칠기에 따른 전단 거동을 비교한 그래프이다.

PURPOSES: A tack coat has been utilized to increase the bond performance between the surface layer and base course (intermediate course) at various road pavement sites. This is similarly true in other nations. Based on this connection, the objective of the present study is to evaluate the properties of hot mix asphalt (HMA) mixtures with an RSC-4 or BD-Coat and determine the application rate of the tack coat. METHODS: The HMA specimens were manufactured using superpave gyratory compaction. The HMA mixtures were composed of a 5-cm thick surface layer and a 10-cm thick base course. An impact hammer resonance test (IHRT) and a static load shear test were conducted to evaluate the performance of the HMA mixtures with a tack coat. From these tests, the dynamic moduli related to the high-frequency resistance and interlayer shear strength (ISS) of HMA could be obtained. RESULTS: The results of the dynamic moduli of HMA are discussed based on the resonance frequency (RF). To check the accuracy of the IHRT, we conducted a coherence analysis. A direct shear test using the application of a static load test was carried out to evaluate the interlayer shear strength (ISS) of HMA. CONCLUSIONS: The maximum ISS was demonstrated at an RSC-4 application rate of 462 gsm, and the maximum dynamic modulus was demonstrated at an RSC-4 application rate of 306 gsm. By averaging the results of the ISS, the maximum ISS values were obtained when a BD-Coat application rate of 602 gsm was applied.

Exterior tile setting can be divided into two types: post-bonding method, and pre-bonding method. Pre-bonding method. In pre-bonding method, different from the post-bonding method, the process of background mortaring is eliminated, saving cost of materials, work hour, and labor expenses, and it doesn’t require time for curing. It is proved that pre-bonding method of manufactured PC tile is economical in terms of Life Cycle Cost, because it method is high in stability and reduces a term of work, and cost low in maintaining and repairing. There are many problems in applying pre-bonding method to real construction work, including the efflux of cement pastes during the process of vibration tampering, and the falling off or breaking of PC tile caused by the contact of vibrator, the cost increase that results from manufacturing overly strength-revealing concrete regardless of the strength of concrete used in the manufacturing of PC cotton wall. The purpose of this study, therefore, is to present ways to resolve above problems by using fluidized concrete in PC manufacturing, and, to find out an appropriate mixture of high fluidized concrete used for PC manufacturing, targeting 280kgf/cm² of specified concrete strength by conducting fundamental experiments, and to provide basic data for bringing pre-bonding method of high fluidized concrete tile into practical use. For this purpose, this study compares adhesive strengh between tiles attached on mock experimental structure, with different mixture rate and curing method, and review and compares marginal concrete deformation rate with the drying shrinkage of concrete by imposing vertical compressive loading until the falling-off of concrete

The joints in this construction are formed through the bonding shear evaluation method during the placement of ultra-high-performance concrete (UHPC). The evaluation items include push-off tests for homogeneous UHPC + UHPC. The experimental samples comprised a monolithic placement as the baseline, two levels for the separated placement according to the compression strength of concrete, and five levels for the interface treatment. The bonding shear performance for the homogeneous UHPC + UHPC construction linearly increased with the width and depth of the grooves used for the interface treatment. The increase in the number of grooves and their cross-sectional areas only slightly influenced the bonding shear performance. The optimal interface treatment method for the homogeneous UHPC + UHPC construction grooves was at least 30 mm.

In the KEPIC-SNG, the domestic technical standard of the SC structure, the condition that the baseplate supporting the reinforcing bars is not bonded to the surface plate is suggested. However, if the baseplate is bonded only to the wingplate, all of the rebar loads generated on the baseplate will be transferred to the wingplate. The wingplate is expected to be conservatively designed in spacing and thickness to support the rebar load. In this study, the finite element analysis was carried out according to bonding conditions between surface plate and baseplate. As a result, it was confirmed that the overall structural strength was increased when the baseplate and the surface plate were bonded. Based on this result, it is possible to propose an economical design for the RC-SC connection such as increasing the wingplate spacing.

This study is, when we pour the concrete, doing bonding shear performance evaluation to search the influence about an adhesive interface by a generated cold joint with a retardation time. In conclusion, this experiment shows that the higher a compressive strength of the concrete is, the higher a reduction ratio of the bonding shear strength is, and the instance of a none agitation and a compaction with 15 minutes of a retardation time are the lowest influence in a whole of the results; each of the reduction ratio of the bonding shear strength is approximately 4.5%.

본 연구에서는 모노파일지지구조의 고성능 그라우트연결부의 부착거동을 다루고 있다. 강관파일 연결부의 일체화를 위하여 섬유보강 고성능 그라우트를 개발하였으며, 재령 7일 압축강도 125MPa와 직인장강도 7.5MPa를 나타내었다. 축하중을 받는 상태에서의 그라우트의부착거동을 평가하기 위하여 강관파일에 그라우트를 충진하여 부착실험을 수행하였으며, 그 결과를 기존의 설계기준과 분석하였다. 실험변수는 섬유혼입율 (0%, 0.5% and 0.9%), 섬유의 형상비 (60 and 80)와 전단키의 높이와 간격의 비 (0.013 and 0.056)로 선정하였다. 실험결과 최대부착강도는 30.8MPa로 관찰되었으며, 섬유 혼입율보다는 전단키의 높이와 간격의 비가 부착강도에 영향을 미치는 것으로 분석되었다.

This study was conducted for investigating effect of retardation time of secondary placement on shear bonding strength. Evaluation experiment on the shear bonding performance of UHPC(180MPa level concrete) was conducted according to retardation time and size of specimen. As a result, the smaller the size of specimen, the weaker the measured bonding performance of specimen. Also, comparing specimen which is o minute occurrence time of cold joint with specimen which is after 15 minutes, it showd 70% lesser shear bonding strength.

Asphalt concrete overlay is the most commonly used resurfacing technique for aged concrete pavement. However, the performance of the asphalt concrete overlay depends on how strongly the asphalt layer bond with concrete layer. Weakened bonding at the interface of asphalt and concrete pavement may contain water and deicer and eventually lead to pavement deterioration such as pothole, reflection crack, and concrete degradation. Accordingly, tensile bonding tests were conducted with various water proofing materials and the bonding performances were evaluated by using different pavement material. Emulsified asphalt waterproofing material showed superior quality in bonding, and acrylastic material waterproofing material showed inferior quality in bonding.

Quality of injection sealer for water leakage maintenance be being managed by KS and ISO. However,the test result of bonding performance on the wet surface of concrete have some errors by an experimenter. Therefore this revision standard of test method is proposed by that the new tester is manufactured for solving this errors in this study.