• International Journal of Highway Engineering
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• v.18 no.6
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• pp.123-130
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• 2016

OBJECTIVES : The objective of this research is to determine the moisture resistance of the freeze-thaw process occurring in low-noise porous pavement using either hydrated-lime or anti-freezing agent. Various additives were applied to low-noise porous asphalt, which is actively paved in South Korea, to overcome its disadvantages. Moreover, the optimum contents of hydrated-lime and anti-freezing agent and behavior properties of low-noise porous asphalt layer are determined using dynamic moduli via the freeze-thaw test. METHODS : The low-noise porous asphalt mixtures were made using gyratory compacters to investigate its properties with either hydrated-lime or anti-freezing agent. To determine the dynamic moduli of each mixture, impact resonance test was conducted. The applied standard for the freeze-thaw test of asphalt mixture is ASTM D 6857. The freeze-thaw and impact resonance tests were performed twice at each stage. The behavior properties were defined using finite element method, which was performed using the dynamic modulus data obtained from the freeze-thaw test and resonance frequencies obtained from non-destructive impact test. RESULTS : The results show that the coherence and strength of the low-noise porous asphalt mixture decreased continuously with the increase in the temperature of the mixture. The dynamic modulus of the normal low-noise porous asphalt mixture dramatically decreased after one cycle of freezing and thawing stages, which is more than that of other mixtures containing additives. The damage rate was higher when the freeze-thaw test was repeated. CONCLUSIONS : From the root mean squared error (RMSE) and mean percentage error (MPE) analyses, the addition rates of 1.5% hydrated-lime and 0.5% anti-freezing agent resulted in the strongest mixture having the highest moisture resistance compared to other specimens with each additive in 1 cycle freeze-thaw test. Moreover, the freeze-thaw resistance significantly improved when a hydrated-lime content of 0.5% was applied for the two cycles of the freeze-thaw test. Hence, the optimum contents of both hydrated-lime and anti-freezing agent are 0.5%.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.81-90
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• 2010

This paper describes the results of laboratory and field performance tests on the polymer modified asphalt binder and mixtures developed in this study for porous asphalt pavements. Various physical and mechanical laboratory tests including DSR and BBR tests are performed for two types of modified binders, and one type of binder is selected based on the binder testing results. Mix designs are conducted for the selected asphalt binder and a Japanese modified binder, respectively. Various performance tests including fatigue tests, wheel tracking tests, and moisture susceptibility tests are conducted for the domestic and Japanese porous asphalt mixtures. Test results indicate that the overall performance characteristics of the domestic mixture are similar to or better than those of the Japanese mixture. Based on the laboratory testing results, the domestic porous mixture is applied to a field test section. Periodic field investigations are conducted to evaluate the changes in noise level and air voids with time. The road noise analysis shows that the noise levels of the porous pavement keep increasing and, after two years, are similar to those of SMA pavements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.33-39
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• 2012

More and more pavements are suffering from damage these days due to the below-zero winter temperatures and frequent snowfalls. From this research, the freeze-thawing mechanisms of pavements will be observed, and the freeze-thawing resistance of porous asphalt concrete mixture is to be evaluated according to various assessment methods. The investigation was conducted through applying rigid and flexible pavements to freeze-thawing resistance experiments, which include various experiments such as deformation rate measurements, Lottman tests, repeated cyclic freeze-thawing experiments, stripping resistance tests and so on. Test results revealed that the porous asphalt concrete had less deformations according to temperatures compared to dense-graded asphalt concrete due to the 20% void gap. In addition, according to the freeze-thawing repetition experiments which are effected by moisture, the porous asphalt concrete mixture showed superior resistance to repeated cyclic freeze-thawing compared to other asphalt concrete mixtures due to the drainage and the voids within the specimen.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.77-87
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• 2015

PURPOSES: It is theoretically well known all over the world, that porous hot mixed asphalt (HMA) with hydrated Lime improves moisture and rutting resistance, and reduces pothole occurrence frequency, as well as the life cycle cost (LCC). METHODS : Addictive in the two different formations of the liquid anti-stripping Agent and powder Hydrated-Lime was applied in this investigation in order to obtain relatively clear results according to their types and conditions. Firstly, the moisture conditions were set, and applied to the porous HMA mixtures with hydrated lime (anti-stripping agent). Next, it was followed by a non-destructive test with the application of three freeze-thaw cycles, which were individually carried out thrice to compare the results of the dynamic moduli. Lastly, the hydrated lime effect related to moisture sensibility to porous HMA has been verified through the analysis of the modulus results regarding the change rate of dynamic modulus per n-cycle. RESULTS: It is clear from this investigation, that the dynamic modulus is inversely proportional to the change in temperature, as the graph representing the rigidity of the thermorheologically simple (TRS) material showed gradual decline of the dynamic modulus with the increase in temperature. CONCLUSIONS: The porous HMA mixture with the anti-stripping agent (hydrated Lime) has been found to be more moisture resistant to freezing and thawing than the normal porous HMA mixture. It is clear that the hydrated lime helps the HMA mixture to improve its fatigue resistance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.283-290
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• 2020

Porous asphalt pavement is used widely in advanced countries to reduce traffic accidents and noise. On the other hand, it is not applied widely in Korea due to concerns about its durability. This study aims to find a statistical method to improve the durability of porous asphalt pavement. A Cantabro test was selected to test the durability. The Cantabro test was performed on an asphalt mixture made of a binder and aggregate. This test was repeated three times for each of the four groups to obtain the Cantabro loss rate. The average values of each of the four groups satisfied all the reference values. In addition, through an analysis of variance (ANOVA), it was possible to quantitatively classify test groups with differences in durability, thereby finding problems and improving the durability. Furthermore, the Pay Factor method can lead to voluntary improvements in quality, and the Pay factor can be calculated through statistical analysis of limited data. Through the Pay factor, it is possible to induce definite quality improvement of the contractor and continuously improve the durability of the porous asphalt mixture by evaluating the adequacy of the quality standard.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.490-497
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• 2020

Asphalt pavement accounts for more than 90% of the total pavement in Korea. Pavement is most widely constructed among construction structures. The heat transfer characteristics (Thermophysical Properties) of the asphalt pavement cause the heat island effect in downtown areas. An increasing asphalt surface temperature is one of the major causes of damage to asphalt pavement. This study examined the heat transfer characteristic factors according to solar energy accumulation in an asphalt mixture. The specimens (WC-2 & PA-13, Recycled aggregate used WC-2) used in the experiment were compacted with a Gyratory Compactor. The thermo-physical properties (thermal conductivity, specific heat capacity, thermal diffusivity, and thermal emissivity) and solar energy accumulation were evaluated. The thermal accumulation and HFM tests revealed a 1.2- to 2.0-fold difference. This indicates that the thermal conductivity of the asphalt mixture pavement changes with the accumulation of solar energy. An analysis of the correlation of thermal conductivity according to the surface temperature of the asphalt mixture showed that WC-2 was logarithmic, and PA-13 was linear. Experiments on the heat transfer characteristics of asphalt pavement that can be used for thermal failure modeling of asphalt were conducted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.227-233
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• 2020

The demand for porous asphalt mixtures is increasing because it has a range of functions, such as reducing traffic accidents and traffic noise. On the other hand, its application is delayed due to concerns about durability. This study examined the effects of the maximum aggregate size, temperature, and porosity of an asphalt mixture on the durability. To this end, the durability measure was set to the Cantabro loss rate. Mixtures having the same porosity of 20% and the maximum aggregate diameters of 13 mm, 10 mm, and 8 mm were tested at 20℃ and -20℃. Mixtures containing 20% and 22% voids with the same material having the same diameter were tested. With 20% porosity, there was no significant difference in durability when there was a change in the maximum aggregate size. There was a significant difference between 20℃ and -20℃, but no significant difference in durability when there was a 2% difference between 20% and 22%. The significance of this study is that the durability was presented quantitatively by tests and statistical analysis. This research will help improve the durability of porous asphalt mixtures by evaluating the factors affecting the durability quantitatively.

• 한국도로학회:학술대회논문집
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• 2010.03a
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• pp.9-17
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• 2010

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.107-117
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• 2006

Recently, there has been a remarkable trend of using aggregates at sizes smaller than 13 mm for drainage asphalt pavement (DAP) in order to reduce the noise generated between vehicle tires and road surface. These DAPs have their performance and durability seriously worsen after several years in-service due to the clogging of void space and the abrasion. This paper proposes the use of large size aggregates in porous asphalt mixtures to overcome these defects. Results of laboratory and field experiments on asphalt mixtures with several aggregate gradations are investigated and compared. The study focuses on advantages of DAP using large size aggregate and on particle size combinations containing no fine aggregates of size 2.36 mm or less, which have not been considered in current engineering practice.

• International Journal of Highway Engineering
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• v.12 no.1
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• pp.29-37
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• 2010

Porous pavements can provide road users with beneficial characteristics such as skid resistance and surface water drainage under rainy condition, and they cause less tire-road noise than conventional hot mix asphalt(HMA) pavements. However, voids of porous pavements are easily clogged by road debris at early stages, which leads to frequent maintenance works. Therefore, this study focused on the way of minimizing void clogging in porous pavements. During mixture design, the quantity of coarse aggregate has been increased to form many straight void conduits (SVCs) in porous HMAs. These SVCs were found to be effective resisting the void clogging problems. Four different porous HMAs(19mm, 13mm, 10mm, and 8mm) were developed and placed on highway roads. Their performances were validated with field tests during the past four years.