• International Journal of Highway Engineering
• /
• v.7 no.4 s.26
• /
• pp.9-20
• /
• 2005

This study was carried out to select most efficient bonding methods of geogrid at the interface of old concrete pavement before placing asphalt overlay layer for reflection cracking retardation. Three bonding methods, a RSC-4 emulsified asphalt, a compound and an unsaturated polyester resin (UPR) were compared in this study. Three types of asphalt mixture (AC 60-80, RLDPE 8%, PG 76-22) and a dense-graded aggregate were used for overlay asphalt pavement. A reinforcing material which consists of a woven fabric underneath a glass fiber grid was used. An expedite test method which is for simulating mixed mode (mode I and II) fracture test was performed using a wheel tracker in laboratory. Cracking development by load repetition was measured as fatigue life (number of load cycle) and expansion of specimen body were measured for each test specimen. The results showed that UPR was the best and RSC-4 the next. But considering field applicability, RSC-4 was considered as an appropriate choice for bonding reinforcing material.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.533-536
• /
• 2008

This study is the application of phosphate magnesia cement for solidification of soils. The object of the study is the application of the pavment of the farm roads. The new pavement method must be environmental, ecologic and durable. So, for solidification of farm road's soil, we use magnesia cement as quick setting, high strength materials. At magnesia phosphate cement, mixing ratio of mono ammonium phosphate and magnesia is 4:6 and w/b is 50 wt%, it show 14 MPa of compressive strength, and high hydration heat. Solidified soils that mixing ratios of magnesia cement and soil are 4:6 and 5:5 have very high durability for freezing and thawing.

• Journal of Environmental Science International
• /
• v.20 no.4
• /
• pp.465-482
• /
• 2011

To preserve atmospheric environment of urban areas, it needs to create urban space considering air pollution sources and natural and geographical properties such as wind circulation. According to this study could examine climate and environmental characteristics of Daegu and accordingly suggest a climate map in urban environment and an "advice map" in urban planning. The urban area(area paved with asphalt and concrete) of Daegu has increased by more than five times since 1960. In addition, the analysis of thermal environment through satellite data shows that the surface temperature between a place paved with artificial structures and a farmland shows $10{\sim}20^{\circ}C$ difference during the daytime in the summer. Regarding the parks inhibiting the heat island of a city have the small area of trees, and the road paved with concrete is wide so that they hardly serve as the source of heat absorption. As Apsan is located to the south of Daegu and Palgonsan to the north and Daegu has east high west low type, mountain wind from mountains in the south and north passes a city and delivers heat and air pollutions at night. In the west of Daegue, there is the poorest environment and industrial facilities and environmental basic facilities are mostly located, so large residential complexes that are being built around the industrial facilities as if they set up a folding screen and therefore the poor environment is increasingly worse.

• International Journal of Highway Engineering
• /
• v.1 no.1
• /
• pp.97-106
• /
• 1999

This study was conducted to develop a test system for evaluating resistance against reflection cracking in shear mode caused by wheel load in asphalt concrete overlaid on the deteriorated cement concrete pavement. Reflection cracking resistance of selected polymer modified asphalt(PMA) mixtures with and without reinforcement was evaluated using this test system. It was shown that the test results accounted for the effectiveness of materials and reinforcement characteristics in terms of the difference in the resistance against reflection cracking. A shear failure life of a certain mixture was estimated with a high coefficient of determination. when the test results were used in a well known prediction model. Therefore, it seemed to be possible to use this technique for predicting a relative service life of on overlay.

• International Journal of Highway Engineering
• /
• v.19 no.5
• /
• pp.33-42
• /
• 2017

PURPOSES : The purpose of this study is to suggest the construction and quality control method for the re-repair of a deteriorated partial depth repair for sections of Portland cement concrete pavement. METHODS : An experimental construction was conducted to extend the repair width for removing an existing repair section. A removal method was used to ensure early performance for a deteriorated partial depth repair section. Bond strength and split tensile strength were measured at the near vertical interface layer between the existing pavement and repair material. The area was analyzed for various conditions such as the extended repair area and the removing method of the existing repair section. RESULTS : As a result of analysis of bond strength and split tensile strength, the bonding performance of a milling removed section was improved over a cutting and hand breaker removed section. The bond strength was analyzed to increase slightly as the extended repair width for removing the existing repair section increased. The split tensile strength did not show a clear relationship to an increased extended repair width of an existing removed repair section. CONCLUSIONS : The milling removal method should be applied in the removal of existing deteriorated partial depth repair sections. The extended repair width for a re-repair section should be wider than the existing partial depth repair with at least a 75-mm length and width for the bond strength and the split tensile strength.

• International Journal of Highway Engineering
• /
• v.19 no.5
• /
• pp.49-58
• /
• 2017

PURPOSES : The objective of this study is to develop a simple regression model in designing the asphalt concrete (AC) overlay thickness using the Mechanistic-empirical pavement design guide (MEPDG) program. METHODS : To establish the AC overlay design equation, multiple regression analyses were performed based on the synthetic database for AC thickness design, which was generated using the MEPDG program. The climate in Seoul city, a modified Hirsh model for determining dynamic modulus of asphalt material, and a new damaged master curve approach were used in this study. Meanwhile, the proposed rutting model developed in Seoul city was then used to calibrate the rutting model in the MEPDG program. The AC overlay design equation is a function of the total AC thickness, the ratio of AC overlay thickness and existing AC thickness, the ratio of existing AC modulus and AC overlay modulus, the subgrade condition, and the annual average daily truck traffic (AADTT). RESULTS : The regression model was verified by comparing the predicted AC thickness, the AADTT from the model and the MEPDG. The regression model shows a correlation coefficient of 0.98 in determining the AC thickness and 0.97 in determining AADTT. In addition, the data in Seoul city was used to validate the regression model. The result shows that correlation coefficient between the predicted and measured AADTT is 0.64. This indicates that the current model is more accuracy than the previous study which showed a correlation coefficient of 0.427. CONCLUSIONS:The high correlation coefficient values indicate that the regression equations can predict the AC thickness accurately.

• International Journal of Highway Engineering
• /
• v.4 no.3 s.13
• /
• pp.35-42
• /
• 2002

Many temperature-related problems are created in asphalt pavement due to the low temperature. In particular, loss of tensile strength due to low temperature is known to be responsible for thermal failure of pavements in cold regions under $-20^{\circ}C$. The objective of this study is to evaluate characteristics of resistance against low-temperature cracking of polymer asphalt concrete mixtures modified with LDPE and SBS. The test results showed that the mixtures had the maximum indirect tensile strength(ITS) at low temperature ranging from $-10^{\circ}C. It was proved through ITS test that the stress due to differential thermal contraction over the tensile strength did generate internal damage at the temperature below $-20^{\circ}C$. It was shown that the asphalt mixtures modified with polymer had better ITS than the normal asphalt mixture at the temperature below $-20^{\circ}C$. Thus the effect of modification was revealed as tensile strength improvement. From the results of this study, it was recommended that polymer-modified asphalt should be used in order to prevent low-temperature cracking in cold region.

• International Journal of Highway Engineering
• /
• v.15 no.2
• /
• pp.1-9
• /
• 2013

PURPOSES : The PMS(Pavement Management System) has been utilized in order to efficiently allocate the limited budget for the maintenance of national highway system. In the PMS of national highway, surface pavement condition is evaluated by using the VI (Visual Index). However, the VI is determined only by considering the cracking rate (%) and rut depth (mm), which is not reflecting the IRI (International Roughness Index) that is known as an important factor of pavement performance. In this study, the NHPCI (National Highway Pavement Condition Index) which includes the cracking rate (%), rut depth (mm), and IRI (m/km) is suggested for determining the rehabilitation methods group. METHODS : First, the rehabilitation methods performed between 2008 and 2010 on the national highway is classified and then, NHPCI is determined for each rehabilitation method. Next, the NHPCI for each rehabilitation method is grouped through the interval estimation of the population mean and T-test analysis. RESULTS : According to NHPCI range, the rehabilitation methods are divided into four categories: Not Required, Preventive Maintenance, Overlay Treatment (with or without cutting), and Full-scale Treatment (i.e., reconstruction). CONCLUSIONS : Based on this study, it is recommended that the appropriate NHPCI range should be determined through the combination of the rehabilitation categories and Decision Procedure of Pavement Distress Condition Visual Index.

• International Journal of Highway Engineering
• /
• v.15 no.2
• /
• pp.113-119
• /
• 2013

PURPOSES : The objectives of this study are to develop the eco-friendly pavement material using polyurethane binder and evaluate mechanical properties of the developed binder and concrete. METHODS : The bending beam test was conducted to select the sample candidates of polyurethane binder based on the bending strength. The characteristics of viscosity, curing time, and temperature change of sample binder was examined on different temperature conditions. The mechanical properties of polyurethane binder was estimated using the dynamic modulus testing. The indirect tensile strength test was conducted on polyurethane binder concrete with different gradation and binder content for evaluating the mechanical properties of concretes. RESULTS : Based on the beading beam test, four different binder samples were prepared for estimate the mechanical properties. The viscosity of polyurethane binder tends to increase with increase of liquid temperature and the hardening phenomenon begins 10 to 15 minutes at room temperature after mixing the resin and hardener. It is observed that the dynamic modulus of binder increases as loading frequency increases and change of modulus is found to be the highest in the PU-2I binder type. The PU-2I binder concretes shows the largest value of indirect tensile strength and indirect tensile energy. CONCLUSIONS : The use of polyurethane binder as pavement materials is capable of increasing the pavement performance and reducing the detrimental environmental effect during the highway construction.

• International Journal of Highway Engineering
• /
• v.19 no.2
• /
• pp.17-24
• /
• 2017

PURPOSES : This study aims to develop a sealant for use in the installation of Weigh-In-Motion (WIM) sensor for asphalt concrete or cement concrete pavements. METHODS : In order to investigate the properties of various sealants that were mixed with latex and carbon fiber, various test methods were adopted, such as bituminous bond strength test, softening point test, and cone penetration test. To evaluate moisture susceptibility, the BBS test was conducted under moist condition. The bond strength ratio (BSR) was calculated based on tensile strength ratio method. RESULTS : The sealant's properties significantly varied according to the amount of latex or carbon fiber. The usage of latex marginally enhanced the cone penetration test result, notwithstanding reduced asphalt content. This implies that the sealant will be proper cold temperature reason. Moreover, the addition of latex and carbon fiber evidently increased the softening point. This indicates that the tendency of the material to flow at elevated temperatures is encountered during service. With the addition of latex and carbon fiber, the moisture susceptibility measured with BSR improved marginally, while the bond strength under dry condition decreased marginally. Sealant F displays the highest bond strength and BSR under limited test conditions. CONCLUSIONS : According to the proportion of latex and carbon fiber mixed, properties of sealant, such as softening point, cone penetration, and BSR varied marginally. This indicates that the sealant has to be applied considering the environmental condition, to improve service life.