• International Journal of Highway Engineering
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• v.14 no.2
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• pp.11-17
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• 2012

This research describes how to predict a model of the tensile strain related to the fatigue cracking performance of several asphalt concrete structures through design of experiments(e.g., Response Surface Methodology) and harmony search(HS) algorithm. The axisymmetric analysis program of finite element method, which is the KICTPAVE, was used to determine the strain level at the interface layer between asphalt layer and lean concrete layer. Once the training database set of various strain levels was constructed under the several condition of layer stiffnesses and thicknesses in the asphalt concrete structures, the data set was trained through the HS algorithm in order to determine the regression coefficients defined based on a response surface methodology. Furthermore, the testing set, which was not used for the training procedure of HS algorithm, was also constructed in order to evaluate whether the regression coefficients of a prediction model can be appropriately applied for other cases in asphalt concrete structures.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.205-213
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• 2007

Strength relationships are presented through experimental data from the concrete strength tests in this study. Various strength tests such as the compressive, flexural, and splitting tensile strength and the modulus of elasticity are included. An experimental work was performed to determine the various strength characteristics for various mix designs. Three different coarse aggregates such as granite, limestone, sandstone were used and included were fine aggregates such as natural sand, washed sand and crushed sand. Also included was cement amount as experimental variable. It was confirmed that each strength value with respect to curing time is to follow a typical strength development curve. With this somewhat reliable test results various strength relationships such as flexural strength-compressive strength, splitting tensile strength-compressive strength, modulus of elasticity-compressive strength, splitting tensile strength-flexural strength were analyzed through statistics. Experimental data were well fitted to the 0.5-power relationship of flexural strength and compressive strength which has been commonly accepted. The splitting tensile strength is expected to be best in the linear relationship from the flexural strength data. Finally splitting tensile strength was found to be proportional to the 0.87 power of the cylindrical compressive strength.

• International Journal of Highway Engineering
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• v.7 no.2 s.24
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• pp.45-55
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• 2005

It is known that the Q/C(Quality Control) in the early age of portland cement concrete(PCC) pavement gives a huge effect on long term pavement performance. Thus, many studies regarding the construction of PCC pavement have focused on how to assure construction quality at the early age stage. Curing is one of the most important factor in Q/C of PCC pavement. Membrane curing that protects the evaporation of moisture by placing an impermeable layer on the slab surface is the most common practice for curing the PCC pavement. In order to improve the membrane curing practice, the rate of curing compound should be optimized. However, the optimum rate of curing compound considering Korean weather and environmental conditions has not been specified in the pavement construction specifications. In this study, a proper application rate was recommended in terms of minimizing evaporation with several full-scale tests where various rates of curing compound have been applied. Four test sites on the expressway were enlisted during the summer of 2002 and 2003. Application rates tested were in the range of $0. The rate of evaporation, the temperature pattern of the slab and the pulse velocity of concrete surface have been monitored at each test construction. The result from this study showed that the rate of current construction was approximately $160ml/m^2$ and that approximately $400ml/m^2$ of curing application was recommended as the proper rate for minimizing the moisture evaporation.

• Resources Recycling
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• v.19 no.6
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• pp.36-42
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• 2010

Researches on resources recycling in the field of construction have made an extensive progress such as recycled aggregate of waste concrete and recycling of asphalt. On the other hand, there are almost never researches on pavement method with used waste frying oil. In South Korea, 0.2 million ton used waste frying oil is discharged every year. It is guessed that about 0.1 million ton used waste frying oil can be collected. If used waste frying oil is recycled, it is expected that disuse cost will be reduced and water pollution of rivers will be prevented. Therefore, the purpose of the study was to evaluate on mechanical features (strength, water resistance, chemical resistance, abrasion resistance, freezing and thawing resistance and permeable coefficient) whether dense graded permeable concrete mixing silica sand with flexible alkyd resin manufactured by making ester reaction with collected used waste frying oil to make alkyd resin could be applied to road pavement for non-roadway. The results of the study were as follows. In flexural strength, it had 1.6 times as much as road design standard 4.5MPa. In water resistance, chemistry resistance and freezing and thawing resistance, they had lack of strength in early age. As age went by, they didn't have large changes. And curing temperature had phenomenon of increase in strength at rather low temperature than high temperature by glass transition temperature of resin. Therefore, considering workability, strength and durability when it was applied to road pavement, it was reasonable that the mixing ratio of flexible alkyd resin was 10~15% in comparison with silica sand weight.

• International Journal of Highway Engineering
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• v.8 no.4 s.30
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• pp.87-99
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• 2006

This study was conducted to investigate whether the moisture variation aspects in pavement materials can be analyzed based on the convenient and reliable relative humidity(RH) measurement techniques. First, the ambient RH was measured using various sensors and the accuracies and calibration methods of the sensors were examined. Then, the RH of a cement mortar specimen was measured using the reliable sensors and the data was analyzed. In addition, the feasibility of using the RH measurement sensors to analyze the permeability of pavement materials was investigated. From this study, it was found that the Hygrochron was the most appropriate sensor to measure the RH of pavement materials, and the proper installation and calibration methods were developed. The RH of the cement mortar specimen tended to approach the ambient RH and was not much affected by the variation of the ambient RH. The specimen's RH variations at the surface and at the center showed a clear time lag. The RH measurement sensor was also found to be an appropriate tool for water permeability tests, and the methodologies to evaluate the permeability of pavement materials were proposed.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.1-11
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• 2009

This study focuses on evaluating the applicability of an acryl based polymer concrete to the thin bridge deck pavements. The acryl concrete developed in this study is composed of Methyl Methacrylate(MMA) resin, benzol peroxide and fillers. To study the effects of the types and amounts of the components on the physical characteristics of the acryl concrete, viscosity, compressive strength and bending tests were conducted. The optimum mixture design was then determined based on the testing results. Several different types of laboratory tests, such as water and chlorine ion penetration tests, shrinkage and thermal coefficients tests, and tensile bonding strength tests were performed for the optimum acryl concrete and conventional cement concrete. The testing results show that water and chroline ion resistance, bonding strength between acryl and cement concrete and crack resistance of the acryl concrete is better than those of the conventional cement concrete. There are shortcomings that the conventional acryl concrete has a higher shrinkage and thermal coefficients. However, it was confirmed that to use newly developed rubberized MMA resin in this study reduces the crack resistance with substantially increased ductility.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.103-114
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• 2011

Usage of bicycle has been supported the universal reduction of energy consumption and $CO_2$. For the same purpose, new constructions for long length bike roads are planned in Korea. Recently, laboratory tests of physical properties and resistance against environmental loading about optimum mix design of roller compacted concrete, that have advantages of high structural performance by cement hydration and aggregate interlocking, simple construction procedure and low construction cost, are performed for the effective construction of new bike roads. However, properties of roller compacted concrete had different results between laboratory and field tests since it had different compaction method. Also, construction method of roller compacted concrete are not defined for the application of bike roads since it had different demand performance such as thin pavement thickness, low strength and etc with road pavements. Thus, in this experimental research was launched to evaluate the core properties, visual inspection, compaction ratio, water content, thickness reduction rate of roller compaction, skid resistance and roughness by experimental construction about variable mix proportion and compaction method based on laboratory test results. And construction method of roller compacted concrete pavement were suggested for the application of bike roads.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.31-38
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• 2011

As the percentage of permeable ground is reduced due to the increased impermeable roads of major cities, a heat island phenomenon can be dominantly observed, resulting in increased temperature. In addition, rainfall that would have been naturally absorbed and retained by the permeable ground is overflowed due to large volumes of run-off water, resulting in more sewer failures and increased erosion. In terms of permeable pavement system, block paving has been used anywhere as well as provides many years of service. The permeable block paving is an effective alternative to the more traditional asphalt or plain concrete for minor roads; furthermore, it looks a lot better than other pavements. In this study, the functional drainage evaluation of block paving was carried out, considering the usage of experimental sludge and wheel tracking test, in order to simulate the field condition of roads.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.33-43
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• 2006

Pull-out strength of tie-bin used in pavement construction is not an issue because those are embedded in newly placed concrete slabs. However, sufficient pull-out strength should be secured in widening constructions because, in case, the tie-bars are inserted into drilled holes of the existing slabs with liquid filler. Insufficient pull-out strength will result in lowered load transfer efficiency between adjacent slabs in addition to poor serviceability and durability due to joint widening. The pull-out strength of the tie-bars installed by current method is evaluated and improved methods are proposed. The field pull-out strength obtained by the current method was only 42.7% of required strength. Its first counterproposal is using to insert the liquid filler into drilled holes and stoppers to prevent it from flowing out of the holes. However, this method was not judged to secure desired level of quality control. The second counterproposal which substitutes the existing type of the tie-bars by SL anchor bolts was judged to secure sufficient pull out-strength in addition to the quality control and constructibility.

• International Journal of Highway Engineering
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• v.13 no.2
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• pp.159-166
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• 2011

This research was performed to evaluate physical properties of polysulfide epoxy overlay material for bridge deck as part of a review for possibility of domestic application of polymer concrete for bridge deck pavement. In order to evaluate strength characteristics, compressive strength, flexural strength and bond strength were tested, and, for durability characteristics, chloride ion penetration resistance and freeze/thaw resistance were tested along with ultraviolet rays impact evaluation. The tests showed that the results met the criteria suggested by the American Concrete Institute in terms of compressive strength, flexural strength and bond strength. However, in terms of the strengths measured at various test temperatures, it was found that the epoxy material was highly dependent on temperature, and, therefore, this should be considered at the time of domestic application of the epoxy material later. Deflection characteristics was checked through flexural strength test and it was found that bridge deck pavement using the epoxy material was excellent compared to bridge deck pavement using asphalt. Furthermore, the results of chloride ion penetration resistance test and freeze/thaw resistance test were also excellent. In the evaluation of ultraviolet rays impact on epoxy slurry mixture, reduction of strain was noticed with increased strength, but the deflection characteristics after exposure to ultraviolet rays was better than the existing acryl polymer concrete. Therefore, it is concluded from the research that the polysulfide epoxy overlay material has the physical properties that are appropriate to pavement of bridge deck.