PURPOSES : In this study, we evaluated the quality levels of abrasion resistance and freeze-thaw resistance to the surface layer (colored layer) by using an overseas abrasion resistance test method to confirm the quality suitability of the concrete block surface for a domestic production permeable block. METHODS : In this study, a new evaluation item for increased durability apart from the quality standard of the permeable block was considered, namely, evaluation of the durability of the surface layer and the freeze-thaw resistance of the permeable block itself by EN 1338, ASTM C 779, 994, and GR 4009 (KS F 4419). RESULTS : The abrasion resistance test for the permeable block revealed that there were relative differences according to the different test methods. However, it was observed that if the ASTM C 779 test results did not meet the wear resistance quality standards, it did not satisfy ASTM C 944 and EN 1338. The ASTM C 779 test result was analyzed to have the highest objectivity and discernment, and this test method was proposed as a permeable block wear test method. In addition, the freeze-thaw resistance test method by the GR 4007 standard can be measured by strength, so it is possible to evaluate the resistance of the permeable block through this test method. CONCLUSIONS : The abrasion resistance test and freeze-thaw resistance test can contribute to the improvement of the permeable block when added to the current quality evaluation tests.

PURPOSES : This study was conducted to analyze the problems of the permeable block by objectively evaluating the quality of the permeable block and providing basic data to improve the quality and construction defect of the permeable block pavement in accordance with the continuously increasing demand of the permeable block. METHODS : In this study, we evaluated the current quality standard suitability of nine products to evaluate the current quality level of domestic production permeable blocks. The evaluation items were evaluated for surface layer thickness, block dimension, strength, and permeability coefficient, and the Korea Standard suitability for these evaluation items was analyzed. In addition, a three-dimensional finite element analysis was conducted to determine the effect of vehicle load on the deformation of block pavement structure. RESULTS : The results demonstrated that the surface layer (colored layer) thicknesses of domestically produced permeable block products were different according to the quality standards, and the dimensions were evaluated to be excellent for domestic permeable blocks currently being produced and delivered. In addition, the strength and permeability coefficient evaluation result demonstrated that all products meet the strength and permeability coefficient quality standards, but the correlation between these strengths and permeability coefficients is not high. The quality standard of strength and permeability coefficients is evaluated as being sufficiently achieved by domestic production technology. CONCLUSIONS: The intensity and permeability coefficients measured in this study were in line with the quality standards; however, the variable coefficient was found to have a significant difference in the quality control level from a maximum of 26% to a minimum 1.7%.

PURPOSES : This study establishes a pay adjustment factor scheme that will penalize or provide incentives to contractors after pavement construction in Seoul City. METHODS: Random sampling was conducted, wherein acceptable quality characteristics (AQCs) of the field mixture such as the aggregate gradation, asphalt binder content, pavement thickness, field air void, and IRI (International Roughness Index) were determined. Using the acquired field data, the percent within limit (PWL) values of each AQC were determined. RESULTS : Weight factors were used to consider the effect of each AQC, since field data varies depending on the field condition. The total pay factor (PF) was determined by combining the PF material and PF construction. PF material considers the asphalt binder content and the aggregate gradation, while PF construction considers the field air void, pavement thickness, and field IRI. CONCLUSIONS: A pay adjustment factor was established by determining the PWL of each AQC and calculating the corresponding pay factor. Based on the results, it is found that PWL is a reasonable and acceptable method for evaluating the pavement quality and determining the pay factor.

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.

PURPOSES: The purpose of this study is to determine the effective maintenance method for a deteriorated jointed plain concrete pavement by evaluating the long-term performance of the repaired concrete overlay sections. METHODS: Long-term performance evaluation was conducted for the test section at the intersection between SeoPa and IlDong in National Road No. 37. Firstly, the distress conditions of the concrete pavement, which was constructed in December 2003, were evaluated by referring to the existing report. Secondly, the results of pretreatment, material properties, and initial performance evaluation were analyzed for the overlay test conducted in 2011. Finally, a field survey was carried out using visual inspection and nondestructive testing with a FWD in August 2018, and long-term performance evaluation was conducted for about seven years after maintenance. RESULTS: Visual inspection of the old concrete pavement showed severe damage such as joint spalling and asphalt patching. The cores taken from the old concrete had indirect tensile strength of 2.6-3.8 MPa. It is difficult to determine the freeze-thaw resistance because the average amount of air was only 1.6-2.2%, and spacing factor values were over 400㎛ regardless of location. During maintenance, overlay and partial depth repair were performed by applying three types of overlay materials which are typical in Korea. On the material side, high compressive strength (over 40 MPa) and chlorine ion penetration resistance (less than 1,000 coulomb) at 56 days were achieved. In August 2018, seven years after maintenance, visual inspection and nondestructive testing using FWD were conducted for long-term performance evaluation. Regardless of the maintenance materials, surface deficiencies such as spalling and map cracking occurred extensively near the joint. CONCLUSIONS: In conclusion, if the strength and durability index of aged concrete pavement is low, then it was determined that partial depth repair at the joint is not an effective maintenance alternative. In the case of overlay, the durability of the overlay material is considered the most important factor. In the absence of adequate reinforcement at the joint of the distressed concrete pavement, freeze-thaw damage caused by moisture penetration through the joint and failure of the old concrete are repeated, making it difficult to ensure long-term durability.

PURPOSES: The permeable pavement type has been rapidly developed for solving problems regarding traffic noise in the area of housing complex and heavy rainwater drainage in order to account for the climate change. In this regards, the objective of this study is to figure out the characteristics of pavement types. METHODS: The laboratory test for deriving optimum asphalt content (OAC) was conducted using the mixtures of the permeable asphalt surface for the pavement surface from Marshall compaction method. Based on its results, the pavement construction at the test field was conducted. After that, the site performance tests for measuring the traffic noise, strength and permeability were carried out for the relative evaluation in 2 months after the traffic opening. The specific site tests are noble close proximity method (NCPX), Light falling deflectometer test (LFWD) and the compact permeability test. RESULTS : The ordered highest values of the traffic noise level can be found such as normal dense graded asphalt, drainage and porous structure types. In the results from LFWD, the strength values of the porous and drainage asphalt types had been lower, but the strength of normal asphalt structure had relatively stayed high. CONCLUSIONS: The porous structure has been shown to perform significantly better in permeability and noise reduction than others. In addition to this study, the evaluation of the properties and the determination of the optimum thickness for the subgrade course under the porous pavement will be conducted using ground investigation technique in the further research.

PURPOSES : The purpose of this study is to develop bridge deck concrete materials based on ordinary Portland cement concrete, and to evaluate the applicability of the developed materials through material properties tests.METHODS : For field implementation, raw material (cement, fine aggregate, and coarse aggregate) properties, fresh concrete properties (slump and air content), strength (compressive, flexural and bond strength) gain, and durability (freeze-thaw resistance, scaling resistance, and rapid chloride penetrating resistance) performance were evaluated in the laboratory.RESULTS: For the selected binder content of 410 kg/m3, W/B = 0.42, and S/a = 0.48, the following material performance results were obtained. Considering the capacity of the deck finisher, a minimum slump of 150 mm was required. At least 6 % of air content was obtained to resist freezethaw damage. In terms of strength, 51.28 MPa of compressive strength, 7.41 MPa of flexural strength, and 2.56 MPa of bond strength at 28 days after construction were obtained. A total of 94.9 % of the relative dynamic modulus of elasticity after 300 cycles of freeze-thaw resistance testing and 0.0056 kg/m2 of weight loss in a scaling resistance test were measured. However, in a chloride ion penetration resistance test, the result of 3,356 Coulomb, which exceeds the threshold value of the standard specification (1000 Coulomb at 56 days) was observed.CONCLUSIONS: Instead of using high-performance modified bridge deck materials such as latex or silica fume, we developed an optimum mix design based on ordinary Portland cement concrete. A test construction was carried out at ramp bridge B (bridge length = 111 m) in Gim Jai City. Immediately after the concrete was poured, the curing compound was applied, and then wet mat curing was applied for 28 days. Considering the fact that cracks did not occur during the monitoring period, the applicability of the developed material is considered to be high.

본 연구에서는 식품용 기구 및 용기·포장으로부터 식 품유사용매로 이행되는 10종의 산화방지제(butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), Cyanox 2246, 425 and 1790, Irgafos 168, 및 Irganox 1010, 1330, 3114 and 1076)의 분석법을 확립하였다. 식품유사용 매 중 물, 4% 초산, 50% 에탄올의 경우 hydrophiliclipophilic balance (HLB) 카트리지로 고체상 추출(SPE, Solid Phase Extraction)을 하였고, n-헵탄의 경우 이소프로 필알콜로 희석하여 HPLC-UVD (276 nm)로 산화방지제의 이행량을 분석하였다. 확립된 분석법으로 위생백, 지퍼백, 우유팩, 주스팩, 가공식품용 포장지, 밀폐용기, 일회용기 등 국내 유통 폴리에틸렌(78건) 및 폴리프로필렌(122건) 재질의 식품용 기구 및 용기·포장 200건으로부터 식품 유사용매로 이행되는 10종의 산화방지제 이행량 조사 결과, 총 78건의 폴리에틸렌 식품용 기구 및 용기·포장 중 5건에서 Irganox 1010이 ND~1.444 mg/L 검출되었고, 총 122건의 폴리프로필렌 식품용 기구 및 용기·포장 중 41건에서 Irganox 1010이 ND~3.106 mg/L, 28건에서 Irganox 1076이 ND~4.752 mg/L, 34건에서 Irgafos 168이 ND~ 3.635 mg/L 검출되어 총 3종의 산화방지제가 검출되었다. 검출된 Irganox 1010, Irganox 1076, Irgafos 168에 대해 일 일추정섭취량(EDI)을 계산하고 일일섭취한계량(TDI)과 비 교하여 위해도를 평가한 결과, 폴리에틸렌 재질 중 Irganox 1010은 TDI 대비 0.0067%, 폴리프로필렌 재질 중 Irganox 1010, Irganox 1076, Irgafos 168은 TDI 대비 0.0073%, 0.1800%, 0.0200%로 안전한 수준임을 확인하였다. 본 연구에서 확립된 폴리에틸렌 및 폴리프로필렌 식품용 기구 및 용기·포장 중 산화방지제 분석법 및 안전성 평가 결과는 앞으로 기구 및 용기·포장의 안전관리를 위한 과학적인 근거자료로 활용될 것으로 판단된다.

PURPOSES : This study is aimed at development of a stochastic pavement deterioration forecasting model using National Highway Pavement Condition Index (NHPCI) to support infrastructure asset management. Using this model, the deterioration process regarding life expectancy, deterioration speed change, and reliability were estimated. METHODS: Eight years of Long-Term Pavement Performance (LTPP) data fused with traffic loads (Equivalent Single Axle Loads; ESAL) and structural capacity (Structural Number of Pavement; SNP) were used for the deterioration modeling. As an ideal stochastic model for asset management, Bayesian Markov multi-state exponential hazard model was introduced. RESULTS: The interval of NHPCI was empirically distributed from 8 to 2, and the estimation functions of individual condition indices (crack, rutting, and IRI) in conjunction with the NHPCI index were suggested. The derived deterioration curve shows that life expectancies for the preventive maintenance level was 8.34 years. The general life expectancy was 12.77 years and located in the statistical interval of 11.10-15.58 years at a 95.5% reliability level. CONCLUSIONS : This study originates and contributes to suggesting a simple way to develop a pavement deterioration model using the total condition index that considers road user satisfaction. A definition for level of service system and the corresponding life expectancies are useful for building long-term maintenance plan, especially in Life Cycle Cost Analysis (LCCA) work.

현재 우리나라 지방자치단체에서 보도의 포장상태를 정량화 할 수 있는 기준이 마련되어있지 않은 것이 현실이며 보도의 포장상태를 조사할 수 있는 방법과 보수기준 수립 역시 부재한 실정이다. 공항, 고속도로, 일반국도, 시도에서 적용되고 있는 포장상태지수는 비교적 다양하게 제시되어 사용되고 있지만, 조사항목과 평가방법이 매우 상이하여 보도 포장에 직접 적용하기에는 무리가 있는 것이 사실이다. 또한, 해외사례의 경우도 대부분 특정결함에 대한 보수기준은 수립되어 있으나, 파손유형을 복합적으로 반영한 평가지수에 대한 사례는 찾아보기 어려웠다. 따라서, 보도포장 유지보수의 근거마련을 위한 종합평가지수의 개발의 필요성이 대두되었고, 본 연구에서는 보도 포장상태를 평가하기 위해 우선적으로 보도의 포장상태를 정량화할 수 있도록 파손분류, 조사방법에 대한 기본방향을 수립하였다. 보도포장에는 포장재료(벽돌, 콘크리트, 화강석 등), 블록형식(I형, O형 등) 등에 따라 다양한 종류의 결함이 확인되고 있으나 결함량에 대한 조사방법은 별도로 수립되어 있지 않은 실정이다. 본 연구에서는 서울시의 보도에 대한 현장조사를 통해 결함의 형태를 분석하여 표 1.과 같이 네 가지 형태의 파손종류를 정의하였다. 블록 깨짐 및 빠짐, 모서리 깨짐, 평탄성 불량, 표면마모 및 박리로 분류할 수 있었으며 기타 특이한 파손은 제외하였다. 보도 포장의 파손면적 측정은 실제 파손구간의 면적을 측정하는 방법이 가장 타당하다고 할 수 있지만, 본 연구에서는 인력조사라는 것과 파손면적 산정의 단순화를 위해 유사한 파손유형을 구룹화하여 직사각형 형태로 파손면적을 측정하는 방법을 적용하였으며, 최소 파손면적은 보수면적 등을 고려하여 1㎡로 설정하였다. 또한 평탄성은 워킹프로파일로미터를 이용하였다. 보도의 포장상태를 정량화 할 수 있는 방법을 제시함으로써 보도의 상태를 나타내는 평가지수를 개발할 수 있는 기반을 마련하였으며 관련전문가의 의견을 청취하여 보도평가지수 개발이 가능할 것으로 판단된다.

지구온난화가 가중되고 도시가 고도화되면서 우리나라 대도시는 여름철 도시열섬이 빈번히 발생하고 있다. 특히 도심부 도로포장의 대부분을 차지하는 아스팔트 포장은 태양광을 흡수하여 노면온도를 상승시키고 야간에 복사열을 배출함으로써 열대야(최저기온이 25℃ 이상 지속)를 발생시키는 주요 원인이 된다. 이러한 도시 열환경 특성은 노약자 건강을 저해하고 시민의 생활불편을 야기하기 때문에 적극적인 개선방안이 필요하다. 이에 일본에서는 2003년부터 ‘환경포장 동경 프로젝트’ 일환으로 차열성 포장이 대안으로 검토되었다. 유럽의 경우 알베도(Albedo)가 높은 골재를 섞은 포장 재료에 대한 연구가 진행되고 있다. 국내에서도 2005년 정부 연구과제로 반사형 도료를 이용한 열섬저감 포장공법이 진행되었으며, 서울시에서는 2009∼2010년 아크릴계 반사형 도료를 이용한 차열성 포장을 개발하여 시험시공을 실시하였다. 일본과 국내에서 차도에 주로 사용하는 MMA(Methyl Methacrylate)계 반사형 도료는 독특한 냄새 때문에 도심 도로에서 넓은 공간 시공 시 주변 도로 이용자에게 불쾌감을 야기한다. 따라서 현장 적용 시 민원발생 우려가 많으므로 MMA와 같은 반사형 도료의 냄새를 저감하고, 이를 평가할 수 있는 방법에 대한 연구가 필요한 실정이다. 본 연구에서는 기존 MMA를 저취형으로 개량하기 위하여 벌크형 중합반응이 아닌 에멀전 중합반응(또는 수용성)으로 MMA를 형성하였다. 이로 인하여 기존 MMA에 비해 내구성과 내마모성이 낮아진 것을 보완하기 위하여 외부 환경에 따라 쉽게 구조가 파괴되는 단량체(Monomer)의 일부를 폴리머(Polymer)로 대체하였다. 다양한 구성비에 대하여 시험한 결과 단량체와 폴리머의 비율이 1 : 3인 경우 최적인 것으로 나타났다. 또한 환경부 악취물질 관련기준과 평가방안(공기희석 관능시험법, KS Q ISO 5496)을 반사형 도료에 대한 정량적 냄새평가 방안으로 제안하였다. 제안된 평가 방안으로 개발된 반사형 도료와 기존 미끄럼방지 포장용 도료를 비교평가 한 결과, 기존 미끄럼방지 포장용 도료의 경우 희석배수가 약 1,442인 반면 개발된 도료의 경우 희석배수가 10 이하로 무취에 가까운 저취형으로 확인되었다. 이를 토대로 향후 반사형 도료에 대한 냄새평가 및 현장적용 가능 여부 판단에 대한 기초자료로 활용될 것을 기대한다.