• Elastomers and Composites
• /
• 제58권2호
• /
• pp.81-86
• /
• 2023

Asphalt pavements are generally composed of fine and coarse aggregates, bitumen, and modifier. Asphalt pavement wear particles (APWPs) are produced by friction between the road surface and the tire tread, and they flow into the environment such as rivers and oceans. Model APWPs were prepared and a single APWP of 212-500 (S-APWP) and 500-1000 ㎛ (L-APWP) was analyzed using thermogravimetric analysis (TGA) to investigate inhomogeneity in the compositions of the APWPs. The reference TGA thermogram was built using thermograms of the raw materials and formulation of the model asphalt pavement. The compositions of the APWPs were different from each other. Ash contents of the APWPs were lower than expected. Inhomogeneity in the total contents of bitumen and modifier was more severe than that in the other components. The inhomogeneity of the S-APWPs was more severe than that of the L-APWPs.

• 한국지반공학회지:지반
• /
• 제3권1호
• /
• pp.39-52
• /
• 1987

말뚝에 작용하는 부주변마찰력의 양상과 감소방법을 일련의 모형실험을 통하여 평가하였다. 감소 방법으로는 역청재와 확대선단부를 사용하였다. 실험은 점성토로 이루어진 모형지반에서 지름이 3.2cm인 모형강관말뚝을 사용하여 수행하였으며 부주변마찰력으로 인한 하향력을 압력계로 측정하였다. 특히 여러가지 경우에 대한 확대선단부의 감소효과는 인발실험을 통하여 알아보았다. 보통말뚝인 경우에 부주변마찰력은 깊이에 따라 0.25(유효상재압)로 나타나며 말뚝과 주변 흙과의 상대변위가 아주 작아도 부주변마찰력은 충분히 발휘된다. 말뚝에 역청재를 도포하여 부주변마찰력을 50%이상 감소시킬 수 있다. 확대선단부의 사용도 ㅂ주 변마찰력의 감소에 효과적이었으며, 말뚝의 지름에 대한 착러설단부의 지름인 커지거나 주변의 강도가 커질수록 그 효과는 커진다. 역청재와 확대선단부를 종시에 사용하던 약 90%의 감소효과가 있다.

• 공업화학
• /
• 제25권1호
• /
• pp.113-115
• /
• 2014

박층의 오일샌드에서 비투멘 성분 회수를 위한 steam assisted gravity drainage 공정에서 무기첨가제 도입에 따른 오일 회수율 특성을 평가하고자 실험실 규모의 모사장치를 이용하여 모사된 오일샌드에서 오일성분을 회수하는 실험을 수행하였다. 오일샌드 모사를 위해 비투멘과 성질이 유사한 초중질유와 직경 1.5 mm의 글래스비드를 사용하였다. 무기합성법을 통해 $FeO_X$를 제조하여 무기첨가제로 도입하였다. 그 결과 시간에 따른 스팀의 열전달 속도는 무기첨가제 도입에 따라 약 40% 증가하였으며, 회수율 또한 약 30% 증가하였다.

• Advances in nano research
• /
• 제4권1호
• /
• pp.15-29
• /
• 2016

A low cost environmentally benign surface coating binder is highly desirable in the field of material science. In this report, castor oil based hyperbranched polyester/bitumen modified fly ash nanocomposites were fabricated to achieve the desired performance. The hyperbranched polyester resin was synthesized by a three-step one pot condensation reaction using monoglyceride of castor oil based carboxyl terminated pre-polymer and 2,2-bis (hydroxymethyl) propionic acid. Also, the bulk fly ash of paper industry waste was converted to hydrophilic nano fly ash by ultrasonication followed by transforming it to an organonano fly ash by the modification with bitumen. The synthesized polyester resin and its nanocomposites were characterized by different analytical and spectroscopic tools. The nanocomposite obtained in presence of 20 wt% styrene (with respect to polyester) was found to be more homogeneous and stable compared to nanocomposite without styrene. The performance in terms of tensile strength, impact resistance, scratch hardness, chemical resistance and thermal stability was found to be improved significantly after formation of nanocomposite compared to the pristine system after curing with bisphenol-A based epoxy and poly(amido amine). The overall results of transmission electron microscopic (TEM) analysis and performance showed good exfoliation of the nano fly ash in the polyester matrix. Thus the studied nanocomposites would open up a new avenue on development of low cost high performing surface coating materials.

• 한국지반공학회논문집
• /
• 제26권11호
• /
• pp.99-110
• /
• 2010

연구에서는 부주면마찰력이 발생하는 3개 지역 총 16본 말뚝의 현장 계측 자료들을 바탕으로 국내 지반 특성에 맞는 주면마찰계수($\alpha$, $\beta$ 계수)의 분포범위를 압밀도(U)와 역청재(S.L) 도포 유무에 따라 역산정하였다. 역청재 도포 말뚝의 부주면마찰력 저감효과는 50~90% 정도인 것으로 나타났으며, 기존 설계에 사용되던 제안 값과의 비교를 통해, 본 연구에서 산정된 $\alpha$와 $\beta$계수가 적정 범위에 있으며, 그 결과 국내지반조건을 반영한 말뚝의 장, 단기 주면마찰력을 예측할 수 있는 기본자료를 제시하였다.

• 한국응용과학기술학회지
• /
• 제40권2호
• /
• pp.332-341
• /
• 2023

오일샌드 테일링의 방류 예정 소식은 찬반 논쟁을 이끌고 있다. 노천광 채굴연계 비투멘 추출공정은 폐수의 발생이 필연적이며, 테일링 인공호수에 저장된다. 현재, 방치된 테일링 인공호수의 규모는 갈수록 그 양이 커지고 있다. 테일링 처리가 매우 어려운 원인으로, 테일링 내의 MFT(mature fine tailings) 층의 생성과 연관이 깊다. 테일링 처리를 위해서는, MFT내에 분산된 미립자를 효과적으로 응집시켜 고체와 액체를 분리하는 핵심 공정이 필요하다. 본 논문에서는 먼저 채굴연계 비투멘 추출공정을 소개하였고, 이를 통해 테일링의 구성 성분과 MFT 특성에 대해서 정리하였다. 또한, MFT 처리공정에 대해 살펴보았다. 향후, 효과적인 고분자 응집제의 선정과 효율적인 탈수공정의 연계성으로 MFT 처리가 성공적으로 진행되기를 기대한다.

• Geomechanics and Engineering
• /
• 제36권1호
• /
• pp.39-50
• /
• 2024

Bitumen and high-quality subangular aggregates, the two principal materials used for asphalt concrete construction, are finite and expensive materials. The general availability of crumb rubber and naturally occurring aggregates of different shapes, especially flat and elongated shapes, indicates that they are feasible alternative materials for expanding the volume of bitumen and utilizing a wider range of aggregate shapes for the development of asphalt concrete, with an associated environmental benefit. The study investigated the effect of adding up to 15% crumb rubber and aggregates sorted into different groups, i.e., rounded, elongated, flat, and their combinations, on the rheological and mechanical properties and durability of 50/70 of hot-mix asphalt pavement. The addition of crumb rubber decreased ductility and penetration but increased the softening point. For a 5.5% bitumen content, asphalt concrete briquettes consisting of 7% crumb rubber and three types of aggregate shapes, i.e., 100% rounded, a mix of 75% rounded and 25% elongated, and a mix of 75% rounded, 15% elongated and 10% flat, were associated with high Marshall stability and indirect tensile strength as well as low lateral deformation due to their high solidity and moderate angularity ratio. Also, the addition of 7% crumb rubber resulted in a significant improvement in the tensile strength ratio and rebound strain of briquettes consisting of 75% rounded and 25% elongated aggregates and those with 75% rounded, 15% elongated and 10% flat aggregates. In relation to the parameters investigated, the three groups of briquettes met some of the local (South Africa) requirements for the surface course and base course of low traffic volume roads.

• Advances in materials Research
• /
• 제13권1호
• /
• pp.63-86
• /
• 2024

Asphalt concrete (AC), is a mixture of bitumen and aggregates, which is very sensitive in the design of flexible pavement. In this study, the Marshall stability of the glass and carbon fiber bituminous concrete was predicted by using Artificial Neural Network (ANN), Support Vector Machine (SVM), Random Forest (RF), and M5P Tree machine learning algorithms. To predict the Marshall stability, nine inputs parameters i.e., Bitumen, Glass and Carbon fibers mixed in 100:0, 75:25, 50:50, 25:75, 0:100 percentage (designated as 100GF:0CF, 75GF:25CF, 50GF:50 CF, 25GF:75CF, 0GF:100CF), Bitumen grade (VG), Fiber length (FL), and Fiber diameter (FD) were utilized from the experimental and literary data. Seven statistical indices i.e., coefficient of correlation (CC), mean absolute error (MAE), root mean squared error (RMSE), relative absolute error (RAE), root relative squared error (RRSE), Scattering index (SI), and BIAS were applied to assess the effectiveness of the developed models. According to the performance evaluation results, Artificial neural network (ANN) was outperforming among other models with CC values as 0.9147 and 0.8648, MAE values as 1.3757 and 1.978, RMSE values as 1.843 and 2.6951, RAE values as 39.88 and 49.31, RRSE values as 40.62 and 50.50, SI values as 0.1379 and 0.2027 and BIAS value as -0.1 290 and -0.2357 in training and testing stage respectively. The Taylor diagram (testing stage) also confirmed that the ANN-based model outperforms the other models. Results of sensitivity analysis showed that the fiber length is the most influential in all nine input parameters whereas the fiber combination of 25GF:75CF was the most effective among all the fiber mixes in Marshall stability.

• 자원환경지질
• /
• 제57권4호
• /
• pp.371-386
• /
• 2024

This paper presents analytical insights regarding into the occurrence of gold within organic matter, which is hosted by solid bitumen and closely associated with uranium ores in the Late Permian Kővágószőllős Sandstone Formation in Western Mecsek, South-West Hungary. The study utilizes a range of analytical techniques, including X-ray powder diffraction (XRPD) and wavelength dispersive X-ray fluorescence (WD-XRF) for comprehensive mineralogical and elemental analysis; organic petrography and electron microprobe analysis for characterizing organic matter; and an organic elemental analyzer for identifying organic compounds. A three-step sequential extraction method was used to liberate gold from organic matter and sulfide minerals, employing KOH, HCl, and aqua regia, followed by inductively coupled plasma optical emission spectroscopy (ICP-OES) to quantify gold contents. The organic matter is identified as comprising two vitrinite types (telinite V1 and reworked V2) and three solid bitumen forms: nonfluorescing (B1) and fluorescing (B2) fillings within the V1, as well as homogenous pyrobitumen (PB) occupying narrow cracks and voids within globular quartz. Despite the samples exhibiting low total organic carbon content (<1 wt%), they display high sulfur content (up to 6 wt%) and the sequentially extracted noble metal content from the organic matter is found to total 7.45 ppm gold. The research findings suggest that organic matter plays crucial roles in ore mineralization processes. Organic matter acts as an active component in the migration of gold, uranium, and hydrocarbons within sulfur-rich hydrothermal fluids. Additionally, organic matter contributes to the entrapment and enrichment of gold in hetero-atomic organic fractions, forming metal-organic compounds. Moreover, uranium inclusions are observed as oxide/phosphate minerals within solid bitumen and associated vitrinite particles. These insights into the occurrence and distribution of gold within organic matter highlight substantial exploration potential, guiding additional research activities focused on organic matter within the Kővágószőllős Sandstone Formation at the Western Mecsek deposit.

• 한국토양비료학회지
• /
• 제18권2호
• /
• pp.121-127
• /
• 1985

토양수분(土壤水分)을 효율적(效率的)으로 관리(管理)할 수 있는 토양개량방법(土壤改良方法)을 구명(究明)하고 토양입단(土壤粒團)의 특성(特性)이 수분변화(水分變化)에 미치는 영향(影響)을 파악(把握)하여 토양구조개선(土壤構造改善)에 적정기준(適正基準)을 제시(提示)하기 위(爲)하여 사양토(砂壤土)와 식양토(埴壤土)에 친수성(親水性)인 Uresol과 소수성(疎水性)인 Bitumen을 처리(處理)하여 시험(試驗)을 실시(實施)하였다. Perspex관(管)을 세토(細土)로 채우고 개량제(改良劑)를 처리(處理)한 토양입단(土壤粒團)과 처리(處理)하지 않은 토양(土壤)을 2cm 두께로 복토(覆土)한 후(後), 인공강우하(人工降雨下)에서 수분(水分)의 침투량(浸透量)을 측정(測定)하고 인공기상조건(人工氣象條件)에서 r-선(線) 수분측정기(水分測定機)를 이용(利用)하여 수분(水分)의 증발량(蒸發量)을 조사(調査)하였다. 토양(土壤)의 수분침투량(水分浸透量)은 친수성(親水性) 토양개량제(土壤改良劑) Uresol 처리(處理)에 의하여 18.7~50.8% 증대(增大)되었으며 소수성(疎水性) Bitumen 처리(處理)는 25% 이하(以下)로 감소(減少)되었다. 증발량(蒸發量)은 Bitumen 처리(處理)로 22.0~68.1%로 억제(抑制)되었으며 Uresol 처리(處理)도 38.7~68.4%로 감소(減少)되었다. 수분침투(水分浸透)와 증발(蒸發)을 합(合)한 총수분이용율(總水分利用率)은 Uresol 처리(處理)에 의하여 2배(倍) 이상(以上) 높일 수 있었다. 토양입단(土壤粒團)의 안정성(安定性), 습윤각(濕潤角)등은 수분(水分)의 침투(浸透)와 증발(蒸發)에 영향(影響)을 끼쳤으며 특(特)히 수분침투(水分浸透)와 습윤각(濕潤角)-안정지수(安定指數), 수분증발(水分蒸發)과 습윤각(濕潤角)-불안정지수(不安定指數)와는 고도(高度)의 유의성(有意性)있는 대수함수적(對數函數的)인 정(正)의 상관(相關)이 있었다. 토양입단(土壤粒團)의 안정성(安定性)은 수분(水分)의 침투(浸透) 및 증발억제(蒸發抑制)와 정상관(正相關)이 있으나 습윤각(濕潤角)의 개선(改善)은 수분침투(水分浸透)와 증발(蒸發)을 모두 증대(增大)시키는 요인(要因)이 되므로 전체적(全體的)인 수분관리면(水分管理面)에서는 토양입단(土壤粒團)의 안정성(安定性)을 증대(增大) 시키는 것이 효율적(效率的)인 것으로 판단(判斷)되었다.