• Land and Housing Review
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• v.10 no.4
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• pp.51-59
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• 2019

The government is encouraging the notice of obligatory reclaimed asphalt as a result of the economic and social positioning of green growth to reduce the amount of waste resources and to solve natural resource problems by recycling continuously generated waste resources. However, it is necessary to develop application guideline for each application to apply reclaimed asphalt to the site because quality control of the reclaimed asphalt is difficult and the specifications are ambiguous as well. Therefore, in this study, the mix design, quality test, performance test, and finite element analysis about reclaimed Asphalt Pavement were conducted to develop application guideline for reclaimed hot asphalt. The mix design was carried out for the comparative general hot mix asphalt mixture, the reclaimed hot mix asphalt mixture using the additive, and the reclaimed hot mix asphalt mixture without the additive. Indirect tensile strength and tensile strength ratio tests were used to characterize the reclaimed hot mix asphalt mixture. Using the results of dynamic modulus test and FWD test for KPRP analysis and finite element analysis, the performance life was evaluated for general pavement and pavement using recycled aggregate. Finally, the life cycle cost analysis was used to compare and analyze the economics of reclaimed asphalt concrete pavement.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.1 s.8
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• pp.133-140
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• 2003

The research was performed to evaluate the cracking resistance characteristics of cold-mixed reclaimed asphalt pavement (RAP) using indirect tensile strength test and fatigue tests. Indirect tensile tests were conducted to estimate the indirect tensile strength at variable temperatures($10^{\circ}C\;and\;20^{\circ}C$). Fatigue tests were also carried out using 500kgf, 400kgf, and 300kgf of dynamic loads, and the fatigue life (Nf) for each mixture was measured. Indirect tensile strength of cold-mixed reclaimed asphalt pavement was about 90% of conventional 13mm dense-graded asphalt mixture. Fatigue life of cold-mixed reclaimed asphalt mixture was 70%, 55%, 30% (for 500kgf, 400kgf, 300kgf of load level, respectively) of the conventional one.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.21-30
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• 2015

PURPOSES : The purpose of this study was to evaluate the performance of rapid-setting polymer-modified asphalt mixtures with a high reclaimed asphalt pavement (RAP) content. METHODS: A literature review revealed that emulsified asphalt is actively used for cold-recycled pavement. First, two types of rapid-setting polymer-modified asphalt emulsion were prepared for application to high-RAP material with no virgin material content. The quick-setting polymer-modified asphalt mixtures using two types of rapid-setting polymer-modified asphalt emulsion were subjected to the following tests: 1) Marshall stability test, 2) water immersion stability test and 3) indirect tensile strength ratio test. RESULTS AND CONCLUSIONS : Additional re-calibration of the RAP was needed for laboratory verification because the results of analyzing RAP aggregates, which were collected from different job sites, did not deviate from the normal range. The Marshall stability of each type of binder under dry conditions was good. However, the Type B mixtures with bio-additives performed better in the water immersion stability test. Moreover, the overall results of the indirect tensile strength test of RAP mixtures with Type B emulsions exceeded 0.7. Further research, consisting of lab testing and on-site application, will be performed to verify the possibility of using RAP for minimizing the closing of roadways.

• International Journal of Highway Engineering
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• v.16 no.4
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• pp.63-74
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• 2014

PURPOSES: This research is to evaluate the mechanical performance of different types of Hot Mix Asphalt (HMA) pavement cells prepared for MN/Road field testing section through an extensive experimental analysis of air voids and simple statistical evaluation tools (i.e. hypothesis test). METHODS: An extensive experimental work was performed to measure air voids in 82 asphalt mixture cores (238 samples in total) obtained from nine different types of road cell located in MN/Road testing field. In order to numerically and quantitatively address the differences in air voids among the different test Cells built in MN/Road, a simple statistical test method (i.e. t-test) with 5% significance was used. RESULTS: Similar trends in air voids content were found among the mixtures including conventional HMA, Reclaimed Asphalt Pavement (RAP) and Warm Mix Asphalt (WMA) combined with taconite aggregate this provides support to the use of RAP and WMA technology in the constructions of asphalt pavement. However, in case of acid modified HMA mixtures, significant differences in air void content were observed between on the wheel path and between wheel path location, which implies negative performances in rutting and thermal cracking resistances. Conclusions : It can be concluded that use of RAP and WMA technology in the construction of conventional asphalt pavement and the use of PPA (Poly Phosphoric Acid) in combinations with SBS (Styrene Butadiene Styrene) in asphalt binder production provide satisfactory performance and, therefore, are highly recommended.

• International Journal of Highway Engineering
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• v.20 no.1
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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.

• International Journal of Highway Engineering
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• v.3 no.1 s.7
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• pp.177-184
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• 2001

A recycling agent has been manufactured on the basis of the chemical composition of reclaimed asphalt binders and virgin asphalt binders. The chemical compositions of reclaimed asphalt binders extracted from reclaimed asphalt pavements have been analyzed according to the ASTM method and the results were compared to those of virgin asphalt binder AP-3. Reclaimed asphalt binders have shown that asphaltenes was increased whereas saturates, naphthene aromatics, and polar aromatics fractions were decreased. A recycling agent made of aromatic compounds, in which its chemical composition is similar to the aromatics fraction in asphalt binders, has been produced to reduce the amount of asphaltenes in reclaimed asphalt hinders. The evaluation of the recycling agent produced was performed by testing ductility, rolling and ball softening point, penetration at $25^{\circ}C$ and viscosity at $60^{\circ}C$. It was found that, by adding the recycling agent 20% by weight to the reclaimed asphalt binders, the physical properties of reclaimed asphalt binders was recovered to the level of virgin asphalt binder AP-3.

• International Journal of Highway Engineering
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• v.19 no.2
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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.

• Magazine of RCR
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• v.15 no.1
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• pp.16-25
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• 2020

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.3
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• pp.1-7
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• 2009

In order to use recycled aggregate as pavement base or subbase materials, the US and many other European countries have started research since the early 1980s. Korea also had a recycle idea as a plan for the vast amount of construction wastes due to the downtown renovation in the 1990s, but was not put into practical use. After the resources saving and recycle expedition law in 1994, wastes from construction sites that have more than a certain amount of construction budget were recycled as pavement base and subbase materials, but now, researches are being conducted to use them as paving materials. The use of construction wastes is meaningful in many ways. It helps the natural conservation and aggregate consumption, and also improves pavement performance. This research presents a development of cold-mixed reclaimed asphalt pavement materials using recycled aggregates.

• Magazine of RCR
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• v.16 no.2
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• pp.40-45
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• 2021