[해외건설서적소개] PAVEMENT DESIGN : MATERIALS, ANALYSIS, AND HIGHWAYS

백철민 대한토목학회 2024 대한토목학회지 Vol.72 No.4

생명(Life)과 의학(Medicine)

백철민 한국자기학회 2022 한국자기학회 학술연구발표회 논문개요집 Vol.32 No.2

도로하부 매설관의 매설심도 및 되메우기 재료가 포장체에 미치는 영향 평가

백철민,김영민,권수안,황성도,김진만 한국도로학회 2013 한국도로학회논문집 Vol.15 No.2

PURPOSES: Compared to the criteria from advanced countries, Korea has conservative criteria for the buried depth of pipeline (about 30~70cm deeper) causing the waste of cost and time. Therefore, this research investigated the effect of various buried depths of pipeline on pavement performance in order to modify the criteria to be safe but economical. In addition, a recycled aggregate which is effective in economical and environmental aspect was evaluated to be used as a refilling material. METHODS : In this study, total 10 pilot sections which are composed with various combinations of pavement structure, buried depth of pipeline, and refilling material were constructed and the telecom cable was utilized as a buried pipeline. During construction, LFWD (Light Falling Weight Deflectometer) tests were conducted on each layer to measure the structural capacity of underlying layers. After the construction is completed, FWD (Falling Weight Deflectometer) tests and moving load tests were performed on top of the asphalt pavement surface. RESULTS : It was found from the LFWD and FWD test results that as the buried depth decrease, the deflections in subbase and surface layer were increased by 30% and 5~10%, respectively, but the deflection in base layer remained the same. In the moving load test, the longitudinal maximum strain was increased by 30% for 120mm of buried depth case and 5% for 100mm of buried depth case. Regarding the effect of refilling material, it was observed that the deflections in subbase and surface layer were 10% lager in recycled aggregate compared to the sand material. CONCLUSIONS : Based on the testing results, it was found that the change in buried depth and refiliing material would not significantly affect the pavement performance. However, it is noted that the final conclusion should be made based on an intensive structural analysis for the pavement under realistic conditions (i.e., repeated loading and environmental loading) along with the field test results.

고품위화 정제공정 부산물(SDAR) 활용을 위한 첨가제 개발 및 이를 이용한 아스팔트 혼합물의 실내 공용성능 평가

백철민,양성린,황성도 한국도로학회 2016 한국도로학회논문집 Vol.18 No.6

OBJECTIVES: The objective of this research is to develop additives for the modification of Solvent DeAsphalting Residue (SDAR) to be used as pavement materials, and evaluate the performance of asphalt mixture manufactured using the SDAR modified by developed additives. METHODS: The SDAR generally consists of more asphaltenes and less oil components compared to the conventional asphalt binder, and hence, the chemical/physical properties of SDAR are different from that of conventional asphalt binder. In this research, the additives are developed using the low molecular oil-based plasticizer to improve the properties of SDAR. First, the chemical property of two SDARs is analyzed using SARA (saturate, aromatic, resin, and asphaltene) method. The physical/rheological properties of SDARs and SDARs containing additives are also evaluated based on PG-grade method and dynamic shear-modulus master curve. Second, various laboratory tests are conducted for the asphalt mixture manufactured using the SDAR modified with additives. The laboratory tests conducted in this study include the mix design, compactibility analysis, indirect tensile test for moisture susceptibility, dynamic modulus test for rheological property, wheeltracking test for rutting performance, and direct tension fatigue test for cracking performance. RESULTS : The PG-grade of SDARs is higher than PG 76 in high temperature grades and immeasurable in low temperature grades. The dynamic shear modulus of SDARs is much higher than that of conventional asphalt, but the modified SDARs with additives show similar modulus compared to that of conventional asphalt. The moisture susceptibility of asphalt mixture with modified SDARs is good if, the antistripping agent is included. The performance (dynamic modulus, rutting resistance, and fatigue resistance) of asphalt mixture with modified SDARs is comparable to that of conventional asphalt mixture when appropriate amount of additives is added. CONCLUSIONS: The saturate component of SDARs is much less than that of conventional asphalt, and hence, it is too hard and brittle to be used as pavement materials. However, the modified SDARs with developed additives show comparable or better rheological/physical properties compared to that of conventional asphalt depending on the type of SDAR and the amount of additives used.

중온화 액상형 화학첨가제 개발과 이를 적용한 중온 아스팔트의 성능 평가

백철민,양성린,황성도 한국도로학회 2013 한국도로학회논문집 Vol.15 No.4

PURPOSES: The liquid-type chemical warm-mix asphalt (WMA) additive has been developed. This study evaluates the basic properties of the additive and the mechanical properties of WMA asphalt and mixture manufactured by using the newly developed chemical additive. METHODS: First, the newly developed WMA additive was applied to the original asphalt by various composition of additive components and dosage ratio of additive. These WMA asphalt binders were evaluated in terms of penetration, softening point, rotational viscosity, and PG grade. Based on the binder test results, one best candidate was chosen to apply to the mixture and then the mechanical properties of WMA mixture were evaluated for moisture susceptibility, dynamic modulus, and rutting and fatigue resistance. RESULTS : According to the binder test, WMA asphalt binders showed the similar properties to the original asphalt binder except the penetraion index of WMA additive was a little higher than original binder. From the Superpave mix design, the optimum asphalt content and volumetric properties of WMA mixture were almost the same with those of hot mix asphalt (HMA) mixture even though the production and compaction temperatures were 30℃ lower for the WMA mixture. From the first set of performance evaluation, it was found that the WMA mixture would have some problem in moisture susceptibility. The additive was modified to improve the resistance to moisture and the second set of performance evaluation showed that the WMA mixture with modified chemical additive would have the similar performance to HMA mixture. CONCLUSIONS : Based on the various laboratory tests, it was concluded that the newly developed chemical WMA additve could be successfully used to produce the WMA mixture with the comparable performance to the HMA mixture. These laboratory evaluations should be confirmed by applying this additive to the field and monitoring the long-term performance of the pavement, which are scheduled in the near future.

저분자 가소제를 활용한 Pitch 아스팔트 특성 분석

백철민,양성린,황성도,이문섭 한국도로학회 2014 한국도로학회 학술발표회 논문집 Vol.2014 No.9

현재까지 일반적으로 사용되고 있는 석유제품은 경질원유에 의해 제조되고 있으나, 이러한 원유 매장 량은 1조 배럴 정도로서 2010년 근방에서 원유 생산 정점에 도달한 후에 점차적으로 생산량이 감소할 것 으로 예측되고 있다. 이러한 상황으로 인해 지속가능하고 효율적인 석유대체 에너지의 개발과 이용에 관 한 연구가 활발하게 진행되고 있으며, 아울러 절대적인 수요가 증가하는 원유를 지속적으로 공급받기 위 한 일환으로 심해, 심부, 극지 등이나 오일샌드, 오일셰일 등과 같은 비재래 화석에너지 개발에 관한 관심 이 증가되고 있다. 새로운 중질유분에 대한 경질화 공정이 고도화될수록 정제공정에서 배출되는 경질화 부산물인 아스팔트(Bitumen), 아스팔텐(Asphaltene), 피치(Pitch)는 국내 95%를 차지하고 있는 아스팔 트 포장의 원료로서 활용하는데는 한계가 있다. 즉, 경질화 공정이 고도화됨으로서 고부가 가치의 DAO(DeAsphaltene Oil)의 추출은 증가되고 유분기가 전혀 없는 아스팔트가 생산되기 때문에 현재 사용 되고 있는 아스팔트와는 전혀 다른 아스팔트가 생산되어 포장 재료로서 활용하는데 한계가 있다. 따라서 본 연구에서는 고도 경질화 공정(Solvent DeAsphalting Process, SDA)을 통해 생산된 Pitch 아스팔트를 활용하여 기본 물성 시험을 통한 도로 포장재료로서의 활용 가능성과 함께 다양한 가소제를 통한 개질 효 과 및 기존 아스팔트 포장 재료 대체 효과를 평가하고자 한다.

Transforming variant of Met receptor confers serum independence and anti-apoptotic property and could be involved in the mouse thymic lymphomagenesis

백철민,전성후,장자준,이복순,이재호 생화학분자생물학회 2004 Experimental and molecular medicine Vol.36 No.4

Met tyrosine kinase receptor, the receptor of hepatocyte growth factor/scatter factor (HGF/SF), is present in mouse tissues as two major isoforms differing by a 47-aminoacid segment in the juxtamembrane domain via alternative splicing of exon 14. We found that the smaller isoform of Met (Sm-Met) was highly transformable in both in vitro and in vivo tumorigenesis assays. In this report, close examination of the transforming activity of the Sm-Met showed that the expression of Sm-Met conferred the cells serum independence and antiapoptotic property when treated with doxorubicin. These properties of Sm-Met seemed to be originated from its far longer maintenance of tyrosine kinase activity after the binding of HGF/SF. Interestingly, the longer maintenance of activated status was accompanied with more increase of tyrosine phosphorylation of Stat3 protein. Moreover, we have tried to find (an) animal tumorigenesis model(s) showing the increase in the expression of this transforming variant of Met. In γ- ray-induced mouse thymic lymphoma model, the expression of the mRNAs for Sm-Met was significantly increased as well as those of wild type Met and HGF/SF, suggesting a possible role of the Sm-Met in tumorigenesis in vivo.

탄소중립 사회를 위한 도로정책

백철민 한국도로학회 2021 한국도로학회지 Vol.23 No.4

도로노면 상태조사 및 코어 분석을 통한 아스팔트 포장 성능과 파손원인 평가

백철민,한수현,안덕순,옥창권 한국도로학회 2023 한국도로학회논문집 Vol.25 No.6

PURPOSES : The purpose of this study is to provide basic data to improve the service life of asphalt pavement using basalt aggregate in Jeju Island by evaluating the performance of asphalt pavement through analysis of material and structural aspects. METHODS : To evaluate the performance of Jeju Island's asphalt pavement, cracks, permanent deformation, and longitudinal roughness were analyzed for the Aejo-ro road, which has high traffic and frequent premature damage. Cores were collected from Aejo-ro sections in good condition and damaged condition, and the physical properties of each layer were compared and analyzed. In addition, plate cores were collected from two sections with severe damage and the cause of pavement damage was analyzed in detail. RESULTS : About 45% of the collected cores suffered damage such as layer separation and damage to the lower layer. The asphalt content of surface layer in the damaged section was found to be 1.1% lower on average than that in the good condition section, and the mix gradations generally satisfied the standards. The density difference between the cores of each layer was found to be quite large, and the air voids was found to be at a high level. CONCLUSIONS : Test results on the cores showed that, considering the high absorption ratio of basalt aggregate, the asphalt content was generally low, and the high air voids of the pavement was believed to have had a significant impact on damage. High air voids in asphalt pavement can be caused by poor mixture itself, poor construction management, or a combination of the two factors. Additionally, the separation of each layer is believed to be the cause of premature failure of asphalt pavement.

현무암 골재 아스팔트 혼합물 물성평가 및 현장시공을 통한 보수수준별 공용성능 평가

백철민,한수현,이종원,박희범,양성린,안덕순 한국도로학회 2023 한국도로학회논문집 Vol.25 No.6

PURPOSES : In this study, the basis for improving the maintenance method of road pavement in Jeju Island, where deterioration is accelerating, was presented through field construction and analysis of various combinations of maintenance methods. METHODS : Construction was performed on Jeju Island's Aejo Road, which has high traffic and frequent early damage, using various asphalt mixtures mainly applied in Jeju Island, with different maintenance cross-sections depending on the level of repair. The quality and performance of the asphalt mixture collected during construction were evaluated, and MEPDG was used to analyze the service life according to the type and maintenance level of the mixture. RESULTS : While the mixture for the surface layer satisfied the quality standards and had excellent rutting and moisture resistance performance, the asphalt mixture for the intermediate and base layer did not satisfy the quality standards such as air voids, so it was judged that quality control was necessary during production. The section repaired to the base layer was found to be advantageous for the integrated behavior of the pavement and had the best structural integrity. As a result of predicting the service life, the estimated life of the section where only the surface layer was repaired was analyzed to be approximately 7 years, the section where the intermediate layer was repaired was 14.5 years, and the section where the entire section up to the base layer was repaired was analyzed to be 18 years. CONCLUSIONS : In Jeju Island, where deterioration is accelerating, it was analyzed that when establishing a maintenance plan, it is necessary to consider repairing the middle and base floors in order to secure the designed life of 10 years.