• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.63-71
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• 2005

Asphalt binder grading is to specify quality of asphalt binders relating to pavement performance in orderly manner, and provides the necessary information in selecting the appropriate asphalt binder for the hot mix design. For this purpose, United States has developed the PG-grading in 1995 and is implementing in practice. Recently, this American PG-grading system has been accepted as the domestic binder grading specification. However, the Asian (including Japan and China) and the most European countries are still use the traditional penetration and viscosity specification. The goal of this study lies in analysing the American PG-grading for its justification. As the result, the serious errors are found, and thus, to eliminate the errors, the more precise binder grading equation is introduced, Credibility of this study is checked by predicting the literature rut data with the equations mentioned. The prediction result are validating the claimes made in this study.

• Tunnel and Underground Space
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• v.20 no.1
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• pp.58-64
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• 2010

GLI model was verified to consider the interaction between a ground and a tunnel lining and to rationally reduce the ground load acting on the secondary lining(concrete lining) of a tunnel. In this study, the economy and the construction condition of tunnel concrete linings designed by a conventional frame model at Lot O of OO line were highly enhanced through a field design change using GLI model. For a few safe considerations, not only about 50% saving of reinforcing steel could reduce the material cost but also the wide space between bars could make it easy to pour concrete mix without voids. There was large saving effect of reinforcing steel for poor ground conditions because Terzaghi's load used in the conventional frame model produces too much high loads for those conditions.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.103-111
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• 2010

Recently, usage bicycle has been encouraged to reduce energy consumption and $CO_2$. For this purpose, lots of bike road construction are planned. Typical type of pavement used in bikeroad such as asphalt concrete pavement, portland cement concrete pavement, colored pavement, soil pavement. However, these pavement types may need high construction cost comparing the required capacity of bike road. In this study, roller compacted concrete pavement which are economical and durable, are investigated to use as bike road pavement. The optimum compaction level and mix design of roller compacted concrete pavement are suggested by exploring strength test with various mixture ratio and compaction level, Also durability was examined based on freeze-thaw and scaling test. In addition, the cost and amount of carbon emission during in the construction of roller compacted concrete were evaluated and compare with the cost and carbon emission of typical portland cement concrete.

• Journal of the Korea Concrete Institute
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• v.17 no.5 s.89
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• pp.821-828
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• 2005

To investigate the role of RH and temperature on the transport of chloride in the concrete, two groups of specimens were configured. For both groups, mix design was based on w/c=0.45, $400kg/m^3$ cement, $794kg/m^3$ fine aggregate and $858kg/m^3$ coarse aggregate. After specimen fabrication these were exposed to four different RH (35, 55, 75 and $95\%$ RH) and temperature (0, 20, 30 and $40^{\circ}C$) conditions. After 3 and 6 months $15\%$ NaCl exposure 5mm cores were taken. These cores were sliced and individual cores were ground to powder. In addition, to evaluate the effect of temperature on the chloride binding some powder samples were leached in the each of four temperature chambers. Chloride titration fur these was performed using FDOT acid titration method. Based upon the resultant data conclusions were reached regarding that 1) effective diffusion coefficient, $D_e$, increased with increasing exposure RH, suggesting that the size and number of water paths increased with elevated moisture content in the specimens, 2) $D_e$ increased with increasing temperature in the range of 0 to $40^{\circ}C$ possibly by elevated thermal activation of chloride ions and reduced chloride binding at higher temperature, 3) water soluble chloride concentration, $[Cl^-]_s$, increased with increasing temperature, and 4) chloride concentration profile for initially dry concrete specimens was higher than for the initially wet ones indicating pronounced capillary suction (sorption) occurred for the dry concrete specimens.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.3
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• pp.305-312
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• 2017

This paper presents a laboratory investigation into the effects of fillers using industrial by-product such as coal ash, IGCC slag on properties of hot-mixed asphalt concrete variation with filler content. For comparison, existing mixture with lime and dust have also been considered. Marshall and flow test has been considered for the purpose of mix design as well as evaluation of mixture. Other performance tests such as indirect tensile strength test, tensile strength ratio(moisture susceptibility), dynamic stability have also been carried out variation with filler content. It is observed that the mixes with industrial by-product exhibit conform with quality standard. Therefore, it has been recommended to utilize industrial by-product based on fly ash wherever available, not only reducing the produce cost but also partly solve the industrial by-product utilization and disposal problem.

• 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.

• Journal of Korean Society of Steel Construction
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• v.11 no.2 s.39
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• pp.223-232
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• 1999

For the design and maintenance of highways and road structures, the statistical data are needed for the vehicle, especially heavy truck crossing. So far, static weighing has been used but it needs fixed station, crews, and it takes a lot of time. Also truck mix and headway distances cannot be obtained. Bridge Weigh-In-Motion system uses the bridge as a weighing scale and collects the axle weights, axle distances. vehicle types and etc. without stopping or slowing down the vehicle. In this study, for the first time in the country, BWIM system is applied on steel I-girder bridge and its applicability is examined. Also data collected in this system is analyzed to get truck traffic characteristics including average daily truck traffic, weight distribution, typical truck configuration and overweight truck status. The results are compared with other data from weighing station and highway toll gates.

• Journal of the Korean Society of Hazard Mitigation
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• v.2 no.2 s.5
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• pp.61-72
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• 2002

The optimum fiber and asphalt binder contents were decided on the base of the Mashall mix design method. To compare the mechanical characteristics between the conventional(dense-graded 20) and the fiber-reinforced mixtures, indirect tension tests were conducted under three temperatures(5, 20, 60$^{\circ}C$). In particular, the wheel tracking tests were performed to evaluate the rutting resistances of the mixtures. Test results showed that the indirect tensile strength of fiber-reinforced asphalt concrete was higher than that of conventional one. The toughness of fiber-reinforced mixture was 1.27 to 1.97 times higher than that of conventional one, depending upon the temperature. In addition, the results of wheel tracking tests and the retained indirect splitting tension tests conducted at $60^{\circ}C$ revealed that the resistance to permanent deformation of fiber-reinforced mixture was stronger than that of the conventional one.

• Explosives and Blasting
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• v.25 no.1
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• pp.53-65
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• 2007

When doing a blasting demolition on RC structures made of scale models, scale model members considering both a proper scale factor and mechanical characteristics of materials have to be similar to prototype RC members to analyze the collapse behavior of RC structures. In this study. a similitude law considering the density of prototype materials is calculated. Both mix of concrete and arrangement of reinforcement have been described referring to Concrete Standard Specification as well as Design Standard of Concrete Structure. The scale factor on scaled concrete models considering maximum size of coarse aggregate is about one-fifth of a cross section of prototype concrete members. A scale factor on staled steel bar models is about one-fifth of a nominal diameter of prototype steel bar. According to the mechanical test results of scale models, it can be concluded that the modified similitude law may be similar to compressive strength of prototype concrete and yield strength of prototype steel bar.

• Computers and Concrete
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• v.12 no.6
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• pp.785-802
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• 2013

Ready-mixed soil material, known as a kind of controlled low-strength material, is a new way of soil cement combination. It can be used as backfill materials. In this paper, artificial neural network and nonlinear regression approach were applied to predict the compressive strength of ready-mixed soil material containing Portland cement, slag, sand, and soil in mixture. The data used for analyzing were obtained from our testing program. In the experiment, we carried out a mix design with three proportions of sand to soil (e.g., 6:4, 5:5, and 4:6). In addition, blast furnace slag partially replaced cement to improve workability, whereas the water-to-binder ratio was fixed. Testing was conducted on samples to estimate its engineering properties as per ASTM such as flowability, strength, and pulse velocity. Based on testing data, the empirical pulse velocity-strength correlation was established by regression method. Next, three topologies of neural network were developed to predict the strength, namely ANN-I, ANN-II, and ANN-III. The first two models are back-propagation feed-forward networks, and the other one is radial basis neural network. The results show that the compressive strength of ready-mixed soil material can be well-predicted from neural networks. Among all currently proposed neural network models, the ANN-I gives the best prediction because it is closest to the actual strength. Moreover, considering combination of pulse velocity and other factors, viz. curing time, and material contents in mixture, the proposed neural networks offer better evaluation than interpolated from pulse velocity only.