PURPOSES : The purpose of this study was to evaluate newly developed Guss mastic asphalt with polymer modifier as a elastomer and a plastomer in to polymer content. METHODS : As polymer modifiers, 10%, 20% of elastomer and 10%, 20% of plastomer, and 10% of elastomer and 10% of plastomer are all added to the binder, and the physical properties of the Guss mastic asphalt mixture with these binders are changed. The properties of mixtures with workability, penetration depth and dynamic stability were compared with the existing Guss mastic asphalt mixture. RESULTS : When using the elastomer and the plastomer, the dynamic stability of the Guss mastic asphalt mixture was improved compared to the conventional asphalt mixture, and when the amount of the elastomer was 20%, the workability was reduced. In addition, when 10% of the elastomer and 10% of the plastomer were used, the workability was not significantly deteriorated and the dynamic stability was increased. CONCLUSIONS : In order to improve the dynamic stability of the Guss mastic asphalt mixture using the polymer-modified binder, it is effective to use an elastomer and a plaststomer.

PURPOSES : This study aims to develop drainage minor-structure materials using asphalt mixtures, and to apply construction methods. METHODS : The AP-5, 120-150A, and 150-200A binders were adopted to select the optimal asphalt binder for the domestic application of asphalt concrete in curb construction. The mixture design of asphalt mixtures has applied the standard for evaluating asphalt curb mixtures in Korea. Test construction utilized asphalt curb equipment to evaluate asphalt mixtures, according to the type of asphalt binder. RESULTS : The results of the asphalt mixture design indicated that the optimum asphalt content was determined at 2–3% air void for each type of asphalt binder, and the quality of the asphalt mixture applied with asphalt curb binder was excellent. In addition, the quality difference was significant, depending on the temperature of the asphalt mixture at each phase of the asphalt curb construction. CONCLUSIONS : Asphalt curb construction using asphalt materials has a large impact on the quality, depending on the temperature of the asphalt mixture, therefore management at the appropriate temperature is important when applying it to the site. Further research is also required on the production, transportation, and dedicated equipment of asphalt mixtures.

PURPOSES : The purpose of this study was to evaluate the newly developed Guss mastic asphalt mixtures, called EQ-mastic asphalt mixtures, which contain melted additives for decreasing cooking time. METHODS : A series of experiments were performed to investigate the effectiveness of the melted additives in EQ-mastic asphalt mixtures. Both the existing Guss mastic asphalt mixture and the EQ-mastic asphalt mixture were produced with the same amounts of asphalt binders, aggregates, and fillers, but the existing Guss mastic asphalt mixture contained 3% Trinidad lake asphalt (TLA). The EQ-mastic asphalt mixture contained 3% of additives, including TLA and polyolefin. The physical material performances of both mastic asphalt mixtures were obtained by conducting the Luer fluidity test, penetration test, dynamic stability test, and low-temperature bending test. The results of the tests for the existing Guss mastic and EQ-mastic asphalt mixtures were compared. RESULTS : The fluidity, penetration, dynamic stability, and low-temperature bending strains of both the existing Guss mastic and EQmastic asphalt mixtures all satisfied the standard values provided in the production and construction guides of the Guss mastic asphalt pavement. CONCLUSIONS : When melted additives containing polyolefin are used in the production of Guss mastic asphalt mixtures, the cooking time decreases, so that the corresponding energy consumption and asphalt fume amount can be reduced. Therefore, an EQ-mastic asphalt mixture is proposed for use as an eco-friendly pavement material.

PURPOSES : The objective of this study is to quantitatively evaluate the visibility of a mixed-color asphalt pavement. METHODS : The visibility was compared and evaluated using a color pavement specimen, i.e., a pigment was added to the asphalt binder, which was used to fabricate a color pavement specimen, with red aggregate as the coarse aggregate, and the resultant difference in visibility was quantitively evaluated. The color asphalt mixture to which the pigment was added was prepared by varying the amount of pigment added — i.e., 3 %, 5 %, and 7 % of the total weight of the mixture — to confirm the change in visibility according to the amount of pigment added. For the color asphalt mixture with color aggregates, red-colored mudstone coarse aggregates(13mm and 10mm) were used. It is assumed that the surface of the produced specimen simulates the initial performance periods and the cut section of the specimen simulates the state of completion of the performance periods. RESULTS : The initial ΔE for the colored pavement exhibited the best visibility of WC-2-R. However, when considering the value of a in the red color pavement, the visibility of SMA13-R and WC-2-R was assessed as best; this is because SMA13-R exhibits a lower color difference than WC-2-R at the beginning of the performance periods but the red color is better. Upon completion of the colored pavement performance periods, the ΔE of each specimen using the SMA13-0C specimen as the reference specimen was high in SMA13-RC and ΔE using the WC-2-0C specimen as the reference specimen was also high in SMA13-RC. In addition, the a value is also higher than that of other mixtures so it is judged that the visibility of SMA13-RC is best when the performance periods are completed. CONCLUSIONS : The a value tended to increase with the increasing amount of pigment added at the beginning of the performance; however, it was found to decrease rapidly as the performance was completed. However, in the case of using SMA13-RC as the colored aggregate, since the color of the aggregate itself is red, it exhibits a constant value of 5.67 from the performance start to completion. Therefore, it is judged that a constant red color can be expressed during the performance period when the colored pavement using red colored aggregate is applied to the exclusive bus lane.

PURPOSES : The cooling characteristics of the asphalt mixture in a moving dump truck were analyzed using a numerical simulation method. The cooling characteristic can be used to determine the optimum transport path for minimizing the temperature drop of the asphalt mixture. METHODS : In this research, a coupled analysis of the discrete element method (DEM) with computational fluid dynamics (CFD) was applied for cooling characteristic analysis of asphalt mixtures in transit. Two different transit speeds, 30 km/h and 60 km/h, were considered to evaluate the effect of speed on the temperature drop of the asphalt mixture. Velocity, pressure, and temperature contours were plotted and temperature variations were compared. RESULTS : Most of the temperature drops in the asphalt mixture were observed in the middle of the dump box in the longitudinal direction. It was confirmed that a faster speed causes a greater temperature drop for the same travel time and a slower speed causes the more temperature to reach the same travel distance as expected. CONCLUSIONS : It is concluded that the coupled analysis method can be used to quantitatively evaluate the effect of vehicle speed on temperature drop in asphalt mixtures. In addition, the method can be used to determine the optimum travel path considering environmental conditions and traffic congestion.

PURPOSES : This paper presents a quality evaluation of Korean foamed asphalt, which uses the maximum expansion ratio and half-life method. The maximum expansion ratio and half-life method are used to determine the optimum water content to produce a foamed asphalt mixture. The foamed asphalt mixture according to determine an optimum water content with this method; the mixture quality was compared with hot mix asphalt mixture. METHODS : For the foamed asphalt mixed design, the water content was determined in addition to the Marshall mixing design method. The water content was determined using the ratio of the maximum to minimum volume and the time for the volume to decrease to half of the maximum volume. We conducted stability, indirect tensile strength, tensile strength ratio, dynamic immersion, and absorption rate tests to compare the foamed and hot mixed asphalt mixtures. RESULTS : The foam asphalt mixture exhibited less performance reduction due to temperature change than the hot mixed asphalt mixture. Most of the two mixture types exhibited similar performance. In addition, both mixtures should use an anti-stripping agent to improve water resistance. CONCLUSIONS : As a result of the laboratory test, the foamed asphalt mixture was able to ensure a similar performance to the hot-mixed asphalt mixture.

PURPOSES : The purpose of this study is to analyze the effect of ions in emulsion asphalt on recycling cold asphalt concrete and suggest the possibility of using anionic and nonionic emulsion asphalt. METHODS : In this study, indirect tensile strength, toughness, tensile strength ratio, and dynamic immersion tests were conducted to determine the effects of cation, anion, and non-ion emulsified asphalt on the cold recycled asphalt mixture. Crack resistance was evaluated through indirect tensile strength and toughness tests and the tensile strength ratio and dynamic immersion test were evaluated through tensile strength ratio and dynamic water immersion test. RESULTS : Indirect tensile strength and toughness measurement results demonstrated that the mixture using anion and non-ion emulsified asphalt tended to be higher than that using cation emulsified asphalt; this is due to the high content of reclaimed asphalt pavement with a cationic or ionic surface, which is related to the use of cation-emulsified asphalt in the mixture and has shown a low strength tendency. The tensile strength ratio measurement demonstrated that the mixture using non-ion emulsified asphalt tended to be approximately 15 % higher than that of the anion mixture. This demonstrated that the chemical additive used in the mixture showed a complete hydration reaction with the distribution to the mixture. The dynamic immersion test indicates that the aggregate film rate of asphalt is highly influenced by the surface electric charge of the new aggregate while the ionicity effect appears to be insignificant, at 75 - 85 %, when circular aggregates are used. CONCLUSIONS : High reclaimed asphalt pavement content in cold recycled asphalt mixture, as well as non-ion and anionic emulsified asphalt, is advantageous, reducing cracking and improving moisture resistance. It is believed that anions and non-ions may be better utilized than applying the existing criteria to the cold temperature recycled asphalt mixture with high reclaimed asphalt pavement content. In addition, if the scope of the emulsified asphalt is expanded, various additives can be used, which will require analysis of materials, such as fertilizers and additives.

PURPOSES : The objective of this study is to address various problems, such as an increase in material cost and premature failure (e.g., cracks and potholes) of porous pavements, and to develop multifunctional asphalt and asphalt mixtures to ensure the long-term commonality of porous asphalt pavements. METHODS : A basic quality test of two types of porous asphalt mixtures was performed. One type consisted of the existing porous asphalt mixture, using domestically presented grading, and the other a porous asphalt mixture using high-viscosity modified asphalt with enhanced low-temperature properties, aimed at improving strain resistance and developed by applying the grading suggested by the Federal Highway Administration (FHWA). RESULTS : The cantabros loss rate was 19.62 % for conventional modified asphalt (PG 82-22) and 5.95 % for the developed highviscosity modified asphalt (PG 88-28), indicating that both mixtures passed the criteria. Regarding the drain-down loss rate, mixtures using both types of asphalt were found to pass all quality standards. The average permeability coefficients for each porous asphalt mixture were 0.023 and 0.018 and both types of porous asphalt mixtures satisfied the quality standard of 0.01 cm/s, as given by the Asphalt Concrete Pavement Guidelines of the Ministry of Land, Infrastructure, and Transport. CONCLUSIONS : As a result of the mix design of the two porous asphalt mixtures, the mixture developed in this study was found to be superior to the conventional porous asphalt mixture using conventional porous asphalt grading and modified asphalt.

PURPOSES : This study was performed to evaluate the short-term aging (SA) protocols of the normal hot-mix asphalt (HMA) mixture, to explore problems, and to suggest proper procedures based on fundamental principles of SA in terms of the SA temperature (T) and length of time (Lt) in existing specifications in several countries including Korea. METHODS : As the SA in our lab is a simulation of field SA, which is an inevitable procedure occurring naturally in the current field practice, major SA guidelines of foreign countries and Korea were reviewed to investigate problems that showed discrepancies with field practice. The aging quantity (Aq) model was introduced as a function of T and Lt, based on the correlation with absolute viscosity (AV) to estimate Aq by T and Lt. The normal SA (NSA) was suggested through an example procedure inducing binder aging level similar to the RTFOtreated binder AV or Aq. Based on the NSA Aq level, lower, proper, or higher SA conditions were discovered from the existing SA guidelines. RESULTS : As Aq has excellent correlation with AV, the proper T and Lt for NSA as an example was suggested based on the AV of RTFOtreated binder to induce an Aq range of 19,000-25,000 min.℃. It was found that there were several problems in the existing guidelines in USA and Korea. These included lower T, shorter or longer Lt, and air blowing or stirring the mix during SA, which were not matched with the practical condition of loaded HMA mixtures that were short-term aged under hot temperatures in trucks. CONCLUSIONS : It was concluded that there are several problems in the current SA guidelines, which do not provide proper HMA temperature to mixtures for proper (modal) length of time. Therefore, these guidelines should be reevaluated carefully and revised based on the fundamental field SA principle. The NSA condition should be suggested using proper HMA T and modal Lt for better simulation of field SA practice.

PURPOSES : Asphalt pavements are damaged by various causes, such as cracks, potholes due to climate, and traffic environment. Asphalt aging has a significant effect on cracks, which may also form potholes. The purposes of this study are to estimate the change in asphalt binder and mixture performance and to correlate the physicochemical changes of the asphalt binder and mixture performance with aging. METHODS : The aging process of the asphalt was determined in the laboratory, based on the methods used in previous studies. In terms of consistency (stiffness), crack-resistance performance, moisture susceptibility, SK investigated the binder part, and Shoreki investigated the mixture part depending on the aging time. RESULTS : The consistency (stiffness) and brittleness of both the asphalt binder and mixture tended to increase with aging. In particular, the crack-resistance performance of the asphalt binder (G*sinδ, ductility, and ΔTc) and mixture (flexural fatigue test and Cantabro test) deteriorated because of asphalt aging. Furthermore, the aging mechanisms (oxidation and polymerization) were identified based on the chemical structure analysis. CONCLUSIONS : It is confirmed that the aging affected the chemical composition change and the physical properties of the asphalt. Asphalt pavements are significantly affected by the aging characteristics of the binder. It is concluded that the crack-resistance performance of the mixture decreases with aging due to these physical and chemical changes.