• 한국도로학회논문집
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• 제15권4호
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• pp.43-51
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• 2013

PURPOSES : The main purposes of this study are to examine the influences of polyethylene wax-based WMA additive on the optimum asphalt content of warm-recycled asphalt mixture based on the Marshall mix design and to evaluate performance of warm-recycled asphalt mixture containing 30% RAP with polyethylene wax-based WMA additive. METHODS: Physical and rheological properties of the residual asphalt were evaluated in terms of penetration, softening point, ductility and performance grade (PG) in order to examine the effects of polyethylene wax-based WMA additive on the residual asphalt. Also, To evaluate performance characteristics of the warm-recycled asphalt mixtures using polyethylene wax-based WMA additive along with a control hot-recycled asphalt mixture, indirect tensile strength test, modified Lottman test, dynamic immersion test, wheel tracking test and dynamic modulus test were conduced in the laboratory. RESULTS : Based on the limited laboratory test results, polyethylene wax-based WMA additive is effective to decrease mixing and compacting temperatures without compromising the volumetric characteristics of warm-recycled asphalt mixtures compared to hot-recycled asphalt mixture. Also, it doesn't affect the optimum asphalt content on recycled-asphalt mixture. All performance test results show that the performance of warm-recycled asphalt mixture using polyethylene wax-based WMA additive is similar to that of a control hot-recycled asphalt mixture. CONCLUSIONS: Overall, the performance of warm-recycled asphalt mixture using polyethylene wax-based WMA additive is comparable to hot-recycled asphalt mixture.

• 한국도로학회논문집
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• 제20권1호
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• pp.97-105
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• 2018

PURPOSES : Asphalt concrete pavement is damaged by various causes such as traffic and environmental loads. The distressed pavement should be maintained by various methods to provide a comfortable and safe pavement for the driver. This study evaluates the effect of adding a mixing procedure to enhance the mixture quality in the hot in-placement recycled asphalt pavement method, which is an asphalt-pavement maintenance method. METHODS : Various test methods such as Marshall stability and dynamic stability, were employed to estimate the recycled asphalt mixture with and without an additional mixing, using the hot in-placement recycled asphalt pavement method. RESULTS : The mixture samples used in this study were taken before and after the addition of the mixer in the hot in-placement recycled asphalt pavement method (HIR) at field construction sites in GongJu and JinJu in South Korea. The test results of both mixtures satisfied the asphalt-mixture standard specifications. CONCLUSIONS : This study confirmed that adding a mixer in the HIR method results in a well-mixed new asphalt mixture, rejuvenator, and reclaimed asphalt mixture.

• 한국건설순환자원학회논문집
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• 제6권3호
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• pp.199-206
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• 2018

아스팔트의 재활용 기술은 화석연료 감소, 탄소 저감, 포장 성능 개선 등의 장점으로 인해 지난 20년간 선진국의 도로 건설 및 유지관리를 위해 개발되고 적용되고 있다. 상온 재생 아스팔트 혼합물은 상온에서 폐아스콘 순환골재를 물과 유화 아스팔트와 함께 혼합하는 역청재료이다. 본 논문은 폐아스콘 순환골재 혼입율에 따라 알칼리 활성화 채움재를 사용한 상온 재생 아스팔트 혼합물의 특성을 검토하고자 하였다. 그 결과 폐아스콘 순환골재의 혼입율이 증가할수록 상온 재생 아스팔트 혼합물의 마샬 안정도가 감소하고 공극률이 증가하였다. 또한, GR에서 정하고 있는 상온 재생 아스팔트 혼합물의 입도 기준을 모든 골재 혼합 조건에서 만족하였다.

• 한국도로학회논문집
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• 제20권4호
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• pp.27-34
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• 2018

PURPOSES : The objective of this study is to evaluate the physical properties of recycled asphalt mixtures reinforced with glass fiber. METHODS : Firstly, mixing design was conducted on recycled asphalt mixture for use of 50% recycled aggregate. Various laboratory tests were performed on four types of recycled asphalt mixtures with different glass fiber content to evaluate the physical properties. The laboratory tests include indirect tensile strength test, dynamic modulus test, Hamburg wheel tracking test and tensile-strength ratio to evaluate cracks, rutting and moisture resistance of mixtures. RESULTS : The indirect tensile strength of fiber reinforced glass increased about 139.4%. As a result of comparing the master curves obtained by the dynamic modulus test, the elasticity was low in the low temperature region and high in the high temperature region when the glass fiber was reinforced. The glass fiber contents of PEGS 0.3%, Micro PPGF 0.1% and Macro PPGF 0.3% showed the highest moisture resistance and rutting resistance. CONCLUSIONS : The test results show that use of glass fiber reinforcement can increase the resistance to cracking, rutting, and moisture damage of asphalt mixtures. It is also necessary to validate the long-term performance of recycled asphalt mixtures with glass fiber using full scale pavement testing and field trial construction.

• 한국도로학회논문집
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• 제20권1호
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• pp.27-33
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• 2018

PURPOSES : The purpose of this study is to estimate the optimum content of an inorganic additive for cold-recycled asphalt mixtures and evaluate its performance. METHODS : An indirect tensile test, a tensile-strength ratio test, and an indirect tensile-fatigue test were conducted on cold-recycling asphalt mixtures with various additives. RESULTS : The laboratory performance tests indicated that granulated blast-furnace slag mixed with inorganic and cement activators provided optimum performance. The performance results of the cold-recycled asphalt pavement were similar to the inorganic and cement activators' performance in terms of the indirect tensile strength, tensile strength ratio, and indirect tensile-fatigue test. CONCLUSIONS : Overall, the performance of a cold-recycled asphalt mixture using inorganic additives and emulsion asphalt was comparable to a warm-recycled asphalt mixture. However, more experiments aimed at improving its performance and studying the effect of the inorganic additives must be conducted.

• 한국도로학회논문집
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• 제19권2호
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• pp.67-74
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• 2017

PURPOSES : The objective of this study is to ascertain the curing period of cementless cold central plant recycled asphalt base-layer, using mechanical analyses and specimen quality tests on the field. METHODS : Cold central plant recycled asphalt base-layer mixture was produced in the plant from reclaimed asphalt, natural aggregate, filler for the cold mix, and the modified emulsion AP using asphalt mix design and plant mix design. In order to examine the applicability of the curing period during the field test, the international standards for the possibility of core extraction and the degree of compaction and LFWD deflection were analyzed. Moreover, Marshall stability test, porosity test, and indirect tensile strength test were performed on the specimens of asphalt mix and plant mix design. RESULTS : The plant production process and compaction method of cementless cold central plant recycled asphalt base-layer were established, and the applicability of the optical moisture content for producing the mixture was verified through the field test. In addition, it was determined that the core extraction method of the conventional international curing standard was insufficient to ensure performance, and the LFWD test demonstrated that the deflection converges after a two-day curing. However, the back-calculation analysis reveals that a three-day curing is satisfactory, resulting in a general level of performance of dense asphalt base-layer. Moreover, from the result of the specimen quality test of the asphalt mix design and plant mix design according to the curing period, it was determined that the qualities satisfied both domestic and international standards, after a two-day curing. However, it was determined that the strength and stiffness after three-day curing are higher than those after a two-day curing by approximately 3.5 % and 20 %, respectively. CONCLUSIONS:A three-day curing period is proposed for the cementless cold central plant recycled asphalt base-layer; this curing period can be demonstrated to retain the modulus of asphalt-base layer in the field and ensure stable quality characteristics.

• 한국도로학회논문집
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• 제19권2호
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• pp.137-142
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• 2017

PURPOSES :The objective of this study is to evaluate the performance of asphalt mixtures containing inorganic additive and a high content of reclaimed asphalt pavement (RAP). METHODS : The laboratory tests verified the superior laboratory performance of inorganic additive compared to cement, in cold recycled asphalt mixtures. To investigate the moisture susceptibility of the specimens, tensile strength ratio (TSR) tests were performed. In addition, dynamic modulus test was conducted to evaluate the performance of cold recycled asphalt mixture. RESULTS :It was determined that NaOH solution mixed with $Na_2SiO_3$ in the ratio 75:10 provides optimum performance. Compared to Type B and C counterparts, Type A mixtures consisting of an inorganic additive performed better in the Indirect tensile strength test, tensile strength ratio test, and dynamic modulus test. CONCLUSIONS : The use of inorganic additive enhances the indirect strength and dynamic modulus performance of the asphalt mixture. However, additional experiments are to be conducted to improve the reliability of the result with respect to the effect of inorganic additive.

• 한국도로학회논문집
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• 제8권4호
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• pp.135-143
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• 2006

본 논문은 가열 재생아스팔트 혼합물의 공용성능 향상을 위한 혼합방법 개발 연구의 일부분이다. 기존 재생혼합물 혼합방법은 재생혼합물 내에서 기존의 노화된 바인더가 균등히 회생되지 않다는 것을 확인하였다. 따라서 새로이 개발된 혼합방법은 회수 아스팔트 포장의 기존 바인더를 기존 재생 혼합방법보다 회수 아스팔트 포장 재료에 묻어 있는 노화된 바인더를 훨씬 많이 회생시켜 재생 혼합물에서 보다 더 균일한 바인더의 점도상태가 되도록 한다. 본 연구의 목적은 새로이 개발된 혼합 방법으로 제조된 재생아스팔트 혼합물의 피로저항 특성을 평가하는 것이다. 두 종류 골재(편마암, 화강암), RAP 15%, LDPE의 두 가지 첨가량(0, 6%)를 이용하였으며, 혼합방법은 바인더의 불균등 상태를 개선하기 위한 두 가지 방법, 즉 일반적인 기존의 O 방법과 새롭게 개발한 N 방법을 이용하였다. 혼합방법에 따른 피로저항성을 평가하기 위하여 혼합방법에 따라 제작한 재생 혼합물의 피로시험을 수행하였다. 그 결과, 피로수명은 O 방법 혼합물이 가장 길고 그 다음이 N 방법이고 control이 가장 낮았다. 또한 장기노화 후 N 방법 혼합물의 균열에 대한 저항성이 O 방법 혼합물에 비해 상대적으로 높아지고 있음을 알 수 있었다.

• 한국지반환경공학회 논문집
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• 제13권2호
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• pp.67-73
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• 2012

폐아스콘은 순재료와 첨가제를 섞어 분쇄와 가열을 통하여 재활용될 수 있다. 본 연구에서는 고품질재생아스팔트(SRP)의 질을 향상시키기 위하여 Sasol 왁스와 폴리올레핀 탄성체를 이용하였다. 첨가제로써 중간층 및 표층용은 PG 70-22를 목표로 아스팔트량의 1.5%를 사용하였고, 중교통 표층용은 PG 76-22를 목표로 아스팔트량의 3% 개질제와 혼합물의 0.1%에 해당하는 셀룰로스 화이버를 첨가하였다. 두 혼합물은 마샬안정도시험, 간접인장강도시험, 잔류간접인장강도시험, 휠트래킹시험 등을 수행하였다. 시험결과는 KS F 2349와 GR F 4005의 기준을 만족하였으며, 고품질재생아스팔트는 중교통도로의 표층 및 기층재료로 사용이 적합하였다. 현재 약 13,000톤의 고품질재생아스팔트 혼합물이 서울 올림픽 도로에 현장시공 되었다.

• 자원리싸이클링
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• 제10권1호
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• pp.32-41
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• 2001

택 코트 사용조건에 따른 재활용 아스팔트 혼합물의 부착전단 강도를 평가하였다 시공온도에 따른 부착전단강도를 평가하여 보면 신재와 구재에 상관없이 시공온도 $30^{\circ}C$에서의 값이 $10^{\circ}C$에 비하여 약 10~20%증가함을 알 수 있었다. 또한 재생아스팔트 혼합물의 경우 택 코트를 사용하지 않았을 때 부착전단강도가 특히 낮아서 현장에서 종종 발생하는 접착면 종방향 균열의 직접적인 원인이 될 수 있음을 나타내었다. 택 코트의 양생시간에 대한 부착전단강도의 영향은 시공온도의 영향보다 대체로 적었다.