• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.595-602
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• 2005

The purpose of this study is to utilize recycled concrete aggregates as permeable pavement materials. This study evaluates mechanical properties and durability of porous concrete depending on mixing rates of recycled aggregates and polyme. As a result, void ratio and permeability coefficient of porous concrete for pavement increased a little as mixing rate of recycled aggregates increased. Void ratio and permeability coefficient increased a lot as mixing rate of polymer increased. As polymer was mixed $20\%$, national regulation of permeable concrete for pavement($8\%$ and 0.01cm/sec) was met. Compressive strength and flexural strength decreased as mixing rate of recycled aggregates increased but they increased a lot as mixing rate of polymer increased. Even when recycled aggregates were mixed $75\%\;with\;10\%$ polymer mixed, national regulation of pavement concrete(18MPa and 4.5MPa) was met. In addition, regarding sliding resistance, BPN increased as mixing rate of recycled aggregates increased. But BPN decreased as polymer was mixed. Compared to crushed stone aggregates, abrasion resistance and freeze-thaw resistance decreased as mixing rate of recycled aggregates Increased. When polymer was mixed, abrasion resistance and freeze-thaw resistance improved remarkably. Compared to non-mixture, $10\%$ mixture of polymer improved abrasion resistance and freeze-thaw resistance about $8.6\%$ and 3.8times respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.717-724
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• 2020

In general, the factors affecting the heat transfer of asphalt pavement are divided into weather factors and pavement materials. Among them, material factors include the thermophysical and surface properties. An experiment was conducted on the thermal-physical factors of asphalt, which are the basis for the pavement failure model. The thermal conductivity, specific heat capacity, thermal diffusivity, and thermal emissivity were evaluated as the thermo-physical properties of asphalt. The specimens (WC-2 & PA-13) used in the experiment were compacted with a Gyratory Compactor. The experimental results of WC-2 and PA-13 showed a thermal conductivity of 1.18W/m·K and 0.9W/m·K, specific heat capacity of 970.8J/kg·K and 960.1J/kg·K, thermal emissivity of 0.9 and 0.91, and thermal diffusivity of 5.15㎡/s and 4.66㎡/s, respectively. Experiments on the heat transfer characteristics (thermo-physical properties) of asphalt pavement that can be used for thermal failure modeling of asphalt were conducted.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.19 no.3
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• pp.1-13
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• 2023

Hydronic heated road pavement (HHP) systems have been well established and documented to provide road safety in winter season over the past two decades. However, most of the systems run on asphalt, only a few are tested with concrete, and there rarely is a comparison between those two common road materials in their performance. The aim of this study is to investigate the thermal performance of the concrete HHP systems, including surface temperature variations of experimental pavements in winter season. For preliminary study a small-scale experimental system was installed to evaluate the heat transfer characteristics of the concrete HHP in the test field. The system consists of 3 concrete slabs made of 1 m in width, 1 m in length, and 0.25 m in height. In these slabs, circulating water piping was embedded with different pipe depths of 0.08 m (Case A), 0.12 m (Case B), and 0.20 m (Case C) and same horizontal space of 0.16 m. Heating performance in winter season was tested with different inlet temperatures of 25℃, 30℃, 35℃ and 40℃ during the entire measurement period. Overall, the surface temperature of the concrete HHPs remained above 3℃ in all experimental conditions applied in this study. The results of the surface temperature measurement with respect to the pipe depth showed that Case B was the highest among the three cases. However, the closer the circulating water pipe was to the pavement surface, the greater the heat exchange rate. This results is considered that the heat is continuously accumulated inside the pavements and then the temperature inside the pavements increases, while the amount of heat dissipation decreases as the temperature difference between the inlet and outlet of circulating water decreases. In this preliminary test the applicability of the concrete HHP on road deicing was confirmed. Finally, the results can be used as a basis for studying the effects of various variables on road pavements through numerical analysis and for conducting large-scale empirical experiments.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.673-678
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• 2010

In this paper, the limit load of granular materials was evaluated considering unsaturated shear strength. The unsaturated shear strength parameters were estimated using the results from triaxial compression test and soil-water characteristic curves test. In addition, the limit load of different rates of materials was compared. Also, two important design parameters, yield and failure load were defined utilizing 2-D nonlinear finite element analysis respectively.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.367-374
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• 2005

In order to construct the farm road in Shi-Hwa project, coarse soils excavated from hillsides have been used as road materials for reclamation. Suitable borrow pits available in land are now limited and also they bring about environmental problems when soils are excavated at the borrow pits and transported to the site. When using fine and wet materials as fill, however, many engineering problems can be encountered. Usually, the materials have high water contents, low strength, and high compressibility. In order to use them, we need research that can improve the inherent properties of those materials. In order to tackle with the problems, researches on soil improvement involve mixing lime geo-cement to the fine wet soils. A lab model test is necessary to verify effectiveness and comparison of those techniques. A field test is also required to show applicability and to find problems that may exist in the design and construction stages.

• Geomechanics and Engineering
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• v.15 no.4
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• pp.1005-1016
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• 2018

This paper presents an investigation on the properties of two types of cement kiln dust (CKD)-stabilized dredged sediments, silt and clay with a comparison to hydrated lime stabilization. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted to examine the optimal stabilizer content and classify the type of highway material. A strength development model of treated dredged sediments was performed. The influences of various stabilizer types and sediment types on UCS were interpreted with the aid of microstructural observations, including X-ray diffraction and scanning electron microscopy analysis. The results of the tests revealed that 6% of lime by dry weight can be suggested as optimal content for the improvement of clay and silt as selected materials. For CKD-stabilized sediment as soil cement subbase material, the use of 8% CKD was suggested as optimal content for clay, whereas 6% CKD was recommended for silt; the overall CBR value agreed with the UCS test. The reaction products calcium silicate hydrate and ettringite are the controlling mechanisms for the mechanical performance of CKD-stabilized sediments, whereas calcium aluminate hydrate is the control for lime-stabilized sediments. These results will contribute to the use of CKD as a sustainable and novel stabilizer for lime in highway material applications.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.239-247
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• 2009

Pipe installation following excavation of pavement and underlying-soils induces settlements, cracks and bad roughness near utility cut. This study is to use PMT and LDWT in order to evaluate stiffness and/or degree of compaction of sublayers and backfill in utility cut section because no specially designed efforts for evaluating stiffness condition of the substructures below new pavement after pipe installation are offered at this time. From test results of PMT, comparable stiffness and/or degree of compaction in recompaction process is not obtained comparing to that of the existing sublayers before excavation. Thickness of the new surface layer after pipe installation must be designed thicker than that of the existing surface layer. It is verified that LDWT comparing to PMT is effective only to get stiffness and/or degree of compaction within limited depth from surface of materials, but it is not useful to evaluate stiffness of substructures in full depth in case of utility cut.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.9-18
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• 2014

PURPOSES : The objective of this study is to evaluate the applicability of the pitch, which is produced during SDA petroleum upgrading process, as a pavement paving material. In order for the purpose, the physical and chemical properties of the pitch are analyzed, and then the various plasticizers are applied in the pitch. METHODS : Two types of pitch are selected from oil refinery companies, which are owned the SDA petroleum upgrading process. Also, two types of asphalt binders, PG 64-22 and PG 58-22, are employed to compare with the pitch because these two types of asphalt binders are currently used as paving materials. For the chemical property of the pitch, the composition of SARA (Saturate, Aromatic, Resin, Asphaltene), the elementary composition, and the functional group are analyzed. For the physical property of the pitch, the basic material property tests, such as penetration test, softening point test, flash point test, ductility test, and rotational viscometer test, are performed. Also, the DSR (Dynamic Shear Rheometer) test and the BBR (Bending Beam Rheometer) test are conducted using asphalt binder specimens obtained by both short term aging (Rolling Thin Film Oven, RTFO) and long term aging (Pressure Aging Vessel, PAV) processes. The rheological property of each pitch type is evaluated as a function of temperatures and loading cycles. PG 64-22 asphalt binder is used as a control material. RESULTS AND CONCLUSIONS : The Pitch may not be suitable for the pavement paving material without modifications, but the pitch can be used as alternatives of modified addictive or asphalt. If low molecular component, such as saturate and aromatic components, are added in the pitch based on the development of various plasticizers, it has a strong possibility for the pitch to be used as a alternative. However, in order to verify the performance property of the pitch, further research is needed.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.603-606
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• 2000

The cost needed for the construction and management of highways in the whole nation is rapidly growing so the research that can decrease the cost is required. However, most of the highway specs have simply converted from those of other countries, including USA. Therefore, some of our design and construction specs were not the optimum ones based on our own situation, requiring a research under the actual traffic and environment of our nation. The use of test road develops many aspects of highway engineering. Those are evaluation of construction materials, a general overview of korea pavement design and serviceability under the actual traffic and environmental condition of the nation. It is also economical and efficient compared to the trial construction of each item in spreaded form. A test road, 7.7km long with two lanes, is being constructed on the Inner Central Expressway. In this test road, 2.7km is planned for asphalt pavement and 3.4km is planned for concrete pavement. Three test bridges and five earth retaining structures will be included in the test road. Based on the master plan, the major performance was progressing such as detailed research modules of each area, preliminary research for the future research, sensor surveys for the behavior analyses of pavements and structures with installation methods and data acquisition systems, the foundation research of Integrated Instrumentation System and the Management Plan for automated measurement. Some area(structure research division, geotechnical research division) was designed the instrumentation plan because some instrument sensors must be installed during the construction of the test road. And then the instrumentation plan of each area was enforcing because a large majority of the instrument sensors must be installed after the construction of the test road. The field surveys with material property tests and pilot instrumentation test with sensor tests was also performing in accordance with the construction in the field.

• Journal of the Korea Institute of Building Construction
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• v.20 no.2
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• pp.113-121
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• 2020

Lots of soil-pavement concrete placed showed a number of problems such as decreasing strength, and durability. In this research, to provide a solution of the problem reported the wasting materials of natural organic lime and magnesia lime were used as a hardener to achieve sufficient performance of soil-pavement concrete. Namely, as a stimulus of blast furnace slag, the natural organic lime and magnesia lime were tested within the mix proportion of 0 to 10 % for each lime to make a new hardener. As a result, in the case of mortar with 1 to 3 % of cement to fine aggregate, 30 % replaced blast furnace slag showed the more favorable results with 5 to 5 % of mix proportion for natural organic lime and magnesia lime.