도로 주행의 안전성 측면에서 타이어-노면간 미끄럼 마찰력은 주행 차량의 제동거리와 직접적인 요인으로 작용한다. 포장재료와 공법은 노출되는 포장 표면에 적절한 노면의 조직(Texture)을 형성하여 노면의 미끄럼 마찰력을 증가시킨다. 도로 표면에 노출되는 사용골재의 크기와 종류를 달리하거나 인위적인 홈을 주어 Macrotexture와 Microtexture를 형성 한다. 형성된 노면 조직은 시간이 경과 됨에 따라 환경하중과 교통하중이 반복 재하되면서 표면마모가 급격히 진행된다. 교통량의 흐름에 따라 마모로 인해 Microtexture 뿐만 아니라 Macrotexture의 노면조직은 매끄러운 표면으로 변해간다. 교통량의 흐름은 다양하다. 교통량 통계자료에 따르면 고속도로 이용차량의 약 70%는 승용차와 같은 2축 1단위로 구성 된 1종 차량이 차지하고 있다. 이는 국내 교통 특성은 포장 마모에 취약한 환경임을 말해주고 있다. 주행 차량들의 좌/ 우 바퀴의 간격과 주행위치의 다른 궤적에 따라 차량바퀴의 횡방향 변동을 원더링(Wandering)이라하는데, 도로포장 분 야에서 교통특성이 포장에 미치는 영향으로 원더링에 대한 연구 많이 진행 되어왔다. 본 연구에서는 실제 고속도로와 시 험도로에서 횡방향 위치별 미끄럼 마찰을 반복 조사하여 차량의 원더링에 따라 미끄럼 마찰저항이 다르게 분포함을 정 량적으로 입증하였다.

PURPOSES: This study was conducted to investigate the causes of damage and to suggest proper repair methods for the sections in which a number of transverse cracks and faulting occurred in JCP (Jointed Concrete Pavement) slabs during the early-age performance period. METHODS: Field crack survey, FWD (Falling Weight Deflectometer) investigation, dowel bar installation condition survey, longitudinal profile survey, and in-situ core specimen inspection were conducted. . RESULTS : As a result of the analysis, it was found that there was no decline in the composite modulus of the subgrade reaction (k-value). The dowel bars were properly installed, but the LTE (Load Transfer Efficiency) of the joint and transverse cracks were analyzed to be very low. In addition, it was found that there are voids in the bottom of the slab at the joints and corners. Due to the excessive built-in curling in the early age of concrete pavement construction, upward curling displacement occurred at the joints and corners, resulting in voids at the bottom of the slab. As a result, it was found that transverse cracks occurred due to the defective joint LTE. CONCLUSIONS: Excessive built-in curling can cause early age cracks in the JCP slabs. In order to minimize the occurrence of reflection cracks after the application of the asphalt overlay in the future, concepts of alternative repair methods were proposed.

PURPOSES : The purpose of this study is to evaluate the performance of road stone block pavements using APT (Accelerated Pavement Testing), which can evaluate the short-term pavement performance of a pavement structure for a given traffic load. METHODS : The performance of stone block, concrete block, and asphalt (modified SMA) pavements were evaluated according to the cumulative equivalent load by using APT. The FWD (Falling Weight Deflectometer) test was used to analyze the deflection per unit load. In addition, the plastic settlement was analyzed by transverse profile measurement. RESULTS: The results of the APT of about 197,000 ESALs (Equivalent Single Axle Loads) show that there were no damages in the stone block, concrete block, and asphalt pavement, such as breakage of stone or concrete block, cracking of asphalt, deflection, and plastic settlement of the wheel-pass section. It was analyzed that the bearing capacity of each pavement section did not decrease sharply with increase in cumulative ESAL. The results of plastic settlement analysis show that in the case of asphalt pavement, the plastic settlement steadily progressed from the beginning of the APT, and a settlement of about 4.76 mm occurred. In the case of concrete block and stone block pavements, no significant change occurred after the initial stabilization step, and plastic settlement of about 1.01 mm and 0.17 mm occurred for the concrete block and stone block pavements, respectively. CONCLUSIONS : As a result of the analysis of the bearing capacity and plastic settlement after the APT, the performance of stone pavement was found to be similar to that of asphalt pavement and concrete block pavement. Therefore, it is concluded that stone pavements are applicable for the road pavement system.

More than sixty percent of highways in Korea were constructed with concrete pavement to carry the heavy traffic loads due to the economic development of this country. The service life of some pavements are close to the end, therefore, they requires the maintenances, rehabilitations and reconstructions to improve their structural performances.According to the similarity of material properties to the concrete pavement, bonded concrete overlay isa good rehabilitation technique used steadily in Korea. However, it is recently reported that the bonded concrete overlays in some highways expose the early distresses and it is assumed that the poor bonding is a cause of this problem. Additionally, the poor bonding of bonded concrete overlay is caused by the bond strength that is less than the bond strength criterion. The pre-investigation of various concrete overlays is conducted in laboratory to determine the possible influence factors reducing the bond strength and it indicates that there are two possible factors affecting the bond strength: the concrete overlay types and the substrate conditions. The study investigates the vulnerable factor between the two factors based on theevaluation of the in-situ bond strength data of bonded concrete overlay gathered from some highways in Korea. The bond strength data is collected from two different application areas: the new constructionand the rehabilitation projects. The new construction and the rehabilitation projects used Latex-modified Concrete (LMC) and Ultra-rapid Hardening Latex-modified concrete (URH-LMC), respectively as the concrete overlay. The evaluation of in-situ bond strength is to determine the percentage of unacceptable bond strength in each projectto study the effect of different types of concrete overlay. Moreover, the percentage of bonding failure modes having the bond strengths less than the criterion is also measured to study the effect of substrate condition.As a result, substrate condition is the vulnerable factor affecting the poor bonding and causing the early distresses in bonded concrete overlay.

Cereal seeds, sorghum, foxtail millet, hog millet, adlay, and corn are traditionally used as health assistant as well as energy supplying food in Korea. While beneficial phytochemicals to human have revealed in cereals, the information on peptides from cereals is far less accumulated than major reserve protein. Here, we analyzed peptide profiles using surface enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF MS) in cereal seeds for construction of peptide information and attempted to develop peptide biomarkers for cereal identification. To optimize the analysis condition of SELDI-TOF MS, the effect of dilution factor on binding affinity to protein chips was tested using CM10 and Q10 arrays. Peptide clusters were significantly different at the level of 0.01 p-value. Peak spectra were the most stable in 1:50 of dilution factor in both chip arrays. Numbers of detected peak of 5 cereal seeds were 131 in CM10 and 74 in Q10 array. Each cereal was grouped as a cluster and well discriminated into different cluster in the level of 0.01 p-value. Numbers of potentially identified peptide biomarkers are 11, 13, 9, 5 and 12 in sorghum, foxtail millet, hog millet, adlay and corn, respectively. This study demonstrates that each cereal seed have own distinguishable specific peptides although their function are not identified yet in this study. In addition, the proteomic profiling using SELDI-TOF MS techniques could be a useful and powerful tool to discover peptide biomarker for discrimination and assess crop species, especially under 20 kDa.