• International Journal of Highway Engineering
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• v.19 no.5
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• pp.117-129
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• 2017

PURPOSES : The purpose of this study is to analyze the performance life of hot central plant recycling (HCPR) and hot in-place recycling (HIR) pavements applied to the National Highway for the past 20 years and compare it with conventional hot-mix asphalt (HMA) pavement. METHODS : In order to analyze the performance life of recycling asphalt pavements, a comprehensive literature review was conducted to investigate the government law and official system for the use of recycling asphalt pavement in Korea and foreign countries. Next, the application information of using a hot central plant recycling and hot in-place recycling pavements in the national highway is collected from the database of pavement management system (PMS) and then their field condition is visually surveyed. Finally, the performance life of recycling asphalt pavements in the national highway is analyzed and compared with conventional hot-mix asphalt pavement. RESULTS :Institutions are encouraging the promotion of using recycled asphalt pavement through various legal systems in Korea as well as abroad. Based on analysis results for the average performance life of hot central plant recycling pavement applied to the national highway, the average performance life is estimated to be 10.2 years. However, the average performance life of in-place recycling pavement is estimated to be 6.5 years. However, it is expected to increase performance life after the HIR construction system is modified. CONCLUSIONS : Based on the limited data analysis of the performance life of recycled asphalt pavements, HCPR shows similar performance life to conventional asphalt pavement but HIR shows shorter performance life than conventional asphalt pavement. However, it is noted that all performance life data is very limited and it should be monitored and analyzed further.

• Structural Engineering and Mechanics
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• v.67 no.3
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• pp.283-290
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• 2018

This paper presents the results of a study that investigated the influence of using recycled coarse aggregate (RCA) and recycled asphalt pavement (RAP) on the properties of pervious concrete (PC). The natural aggregate (NA) was replaced by RCA and RAP in the PC with replacement levels of 0%, 20%, 40%, 60% and 80% by the total weight of NA, respectively. In addition to incorporating RAP and RCA in the same mixes with replacement levels of: (1) 20% RAP and 80% RCA; (2) 60% RAP and 40% RCA; and (3) 80% RAP and 20% RCA. Water permeability, thermal conductivity, density, porosity, void content, and compressive, splitting tensile and flexural strengths were studied in this paper. The results showed that using RCA, RAP, and (RAP-RCA) enhanced the properties of PC in general and improved the mechanical properties significantly in particular. The optimum mix was reported to be the 60% RAP and 40% RCA. Accordingly, the RAP has the potential to be used in PC in order to reduce the negative impact of RAP on the human health and environment.

• Journal of the Korean Geosynthetics Society
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• v.10 no.1
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• pp.37-42
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• 2011

In this study, it is analyzed that mechanical properties and required strength of porous concrete according to the mixing ratio of cement, fine aggregate, and water/cement ratio in order to evaluate mechanical properties of porous concrete using recycled asphalt aggregate. Recycled asphalt aggregates of 13 mm were used without modification of aggregate grading to extend porous concrete application. The water/concrete ratio was poor mix and the range of compressive strength was 18.2 to 19.5 MPa. The average value of permeability showed 8.0E-02 cm/sec.

• Applied Chemistry for Engineering
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• v.17 no.6
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• pp.614-618
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• 2006

Recycling of asphalt including shingle is much important for economic aspects such as a decrease of treatment cost. This research was carried out in order to process the recycled shingle to asphalt concrete which is a pavement material. Pure asphalt and the mixture of recycled asphalt were tested in terms of the thermal characteristics, viscosity, and penetration. DSC analysis indicates that the thermal characteristics of separate shingle showed similar properties regardless of processing conditions. Melting of asphalt separated from shingle occurred at $170^{\circ}C$. The viscosity and penetration of the 1~5 wt% of mixed recycling asphalt and raw material asphalt are suitable for the pavement material standard.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.2
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• pp.51-57
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• 2010

Many models have been used to represent the effects of confining stress, bulk stress, and shear stress on the value of the resilient modulus (Mr). This study was conducted to estimate Mr of the recycled materials such as recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP) through the repeated load cyclic test. Also, two models were applied to estimation of Mr for comparing between measured Mr values and predicted Mr values. The first model (A-model) can provide a quick and easy estimation of the Mr based on the bulk stress, while the second model (N-model) includes not only the bulk stress but also the shear stress. Statistical analysis indicated that all results using the both of models are significant at a 95 % confidence level. Therefore, the both of models could be used as an effective prediction model of Mr for RCA and RAP. Especially, the Model 2 including the parameters of the bulk stress and the shear stress could give more reliable estimation at the high range of Mr values.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.167-176
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• 2021

When producing recycled asphalt mix, it is important that the old binder of reclaimed asphalt pavement(RAP) should be well melted during blending in the mixer. The recycled asphalt mix is produced by instant mixing(IM) of all materials(RAP, virgin asphalt and new aggregates) all together in the mixer. However, in the same recycled mix, the binder around RAP aggregate was found to show higher oxidation level than the binder coated around the virgin aggregate because the old binder of RAP was not rejuvenated properly while instant mixing. The partially-rejuvenated RAP binder is assumed to be a high stiffness point in IM recycled mix. In this study, the stage mixing(SM) method was introduced; blending RAP and virgin asphalt for the first stage, and then mixing all together with hot new aggregates for the second stage. To compare the effect of the two mixing methods on moisture resistance of recycled mixes, a statistical t-test was performed between SM and IM using indirect tensile strength(ITS) and tensile strength ratio(TSR). Three conditioning methods were used; a 16-h freezing and then 24-h submerging, 48-h submerging, and 72-h submerging in 60℃ water. It was found that the TSR(=ITS_wet/ITS_dry) values of the mixes prepared by SM was clearly higher than the IM mixes, and coefficients of variation of SM mixes were lower than the IM mixes. It was also observed that the ITS_WET of SM was significantly different from the IM at α=0.05 level by statistical t-test. The ITS_WET of SM mix was reduced less than the IM mix in severer conditioned mixes. Therefore, it was concluded that the stage mixing method was an important blending technique for producing better-quality of recycled asphalt mixes, which would show higher moisture resistance than the recycled mixes produced by conventional instant mixing.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.113-116
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• 2007

This is a research for evaluated recycled glass powder to add asphalt concrete filler. To make a comparative study, Mechanical performance of lime stone and slag dust Mixtures was evaluated according to test procedure. Lab. performance tests included marshall stability, indirect tensile strength, resilient modulus and wheel tracking. Water resistance tests were evaluated by marshall strength ratio and tensile strength ratio. In conclusion, Results of mechanical performance showed that recycled glass powder mixtures were equivalent to conventional mixtures. Especially, result of tensile strength ratio tested recycled glass powder mixtures was superior to conventional mixtures.

• Magazine of RCR
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• v.4 no.3
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• pp.24-29
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• 2009

• Magazine of RCR
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• v.11 no.2
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• pp.40-47
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• 2016

• Magazine of RCR
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• v.10 no.4
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• pp.28-32
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• 2015