• International Journal of Highway Engineering
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• v.13 no.4
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• pp.81-91
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• 2011

This study was conducted to evaluate the necessity of the anchor lug system in continuously reinforced concrete pavement(CRCP) by comparing longitudinal displacements of CRCPs with and without anchor lugs, and to investigate the effect of horizontal cracking on CRCP performance by measuring the vertical displacements. The measurements before and after the anchor lug section was separated were conducted for 12 days in June, and for 14 days in August after the abrupt displacements according to cutting disappeared, respectively. This short term measurement results showed that when anchor lugs were installed, a daily displacement variation at any location was less than 0.1mm; therefore, longitudinal movements were negligibly small. When there were no anchor lugs, longitudinal displacements mainly occurred near the free end and the displacement variation was small; therefore, an expansion joint system seems to be employed at a CRCP terminus without installing anchor lugs. However, further studies are needed to verify the terminus behavior due to annual temperature changes. The horizontal crack width variation was ignorable and did not affect the vertical displacement of the slab. Therefore, the horizontal crack did not delaminate the slab and did not seem to reduce the structural capacity and performance of CRCP.

• International Journal of Highway Engineering
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• v.16 no.3
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• pp.9-20
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• 2014

PURPOSES : This study is to compare load transfer efficiency of key joint and dowel joint for airport concrete pavement. METHODS : As AC150/5320-6D of FAA's [Advisory Circular] was changed into AC150/5320-6E, Key joint type of rigid pavement were excluded from Construction Joints. LTE(Load Transfer Efficiency) of dowel joint and key joint were compared by times and seasons through pavement temperature measurement, ocular investigation and HWD measurement. RESULTS : For the joint performance grade of No. 2(The second) runway of airport, 12% of poor rate was observed in key joint and 2% of poor rate in dowel joint. Poor rate of key joint was increased to 17%, if only No. 3~No. 6 slabs, which are mostly loaded from the airplanes, were applied for the study. In apron area, LTE poor rate of key joint was high in winter, and LTE poor rate of dowel joint was at least above 'Fair' grade. In summer, 'Fair' for key joint, 'Acceptable' for dowel joint appeared. CONCLUSIONS : As results, dowel joint was superior than key joint for LTE. Deviations of seasons and times were smaller in dowel joint's result. And LTE in winter was lower than LTE in summer.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.19-27
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• 2016

PURPOSES: The behavior of a concrete pavement in a tunnel was investigated, based on temperature data obtained from the field and FEM analysis. METHODS: The concrete pavement in a tunnel was evaluated via two methods. First, temperature data was collected in air and inside the concrete pavement both outside and inside the tunnel. Second, FEM analysis was used to evaluate the stress condition associated with the slab thickness, joint spacing, dowel, and rock foundation, based on temperature data from the field. RESULTS : Temperature monitoring revealed that the temperature change in the tunnel was lower and more stable than that outside the tunnel. Furthermore, the temperature difference between the top and bottom of the slab was lower inside the tunnel than outside. FEM analysis showed that, in many cases, the stress in the concrete pavement in the tunnel was lower than that outside the tunnel. CONCLUSIONS : Temperature monitoring and the behavior of the concrete pavement in the tunnel revealed that, from an environmental point of view, the condition in the tunnel is advantageous to that outside the tunnel. The behavior in the tunnel was significantly less extreme, and therefore the concrete pavement in the tunnel could be designed more economically, than that outside the tunnel.

• Korean Journal of Construction Engineering and Management
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• v.11 no.6
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• pp.111-121
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• 2010

As the customer's interest for sidewalk block in the street or apartment complex is increasing, the materials of block which had been a concrete block exclusively are varied to clay paver, native rock and wood etc. Especially, the sales volume of clay paver which is environment-friendly and ergonomic is dramatically increasing every year with two digits growth rate, however, many problems like "Edge Cracking" "Freezing Breakage" "Bending Breakage" "Joint Gap" are happening frequently within a couple of hours after installation due to the durabilities. Because of the characteristics of Ceramic products, clay pavers are very easy to be broken when they are bumped against each other. In addition, they are relatively fragile by a freezing expansion breakage when exposed to water due to hydrophilic property as well as the intensity and absorptance of the products are varied with small difference from the production process such as production equipment and process control. Therefore, it costs a lot of money to repair the breakdown unless production and installation is carried out according to the strict criteria of the quality control. In this study, the symptoms of breakdown frequently happened in clay paver are classified by each type and finally the solution for this problem in the production of brick, installation and criteria of quality control through compressive strength and absorptance test is suggested.

• International Journal of Highway Engineering
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• v.20 no.3
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• pp.65-73
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• 2018

PURPOSES : In this study, the propriety of expansion joint spacing of airport concrete pavement was examined by using weather and material characteristics. METHODS : A finite element model for simulating airport concrete pavement was developed and blowup occurrence due to temperature increase was analyzed. The critical temperature causing the expansion of concrete slab and blow up at the expansion joint was calculated according to the initial vertical displacement at the joint. The amount of expansion that can occur in the concrete slab for 20 years of design life was calculated by summing the expansion and contraction by temperature, alkali-silica reaction, and drying shrinkage. The effective expansion of pavement section between adjacent expansion joints was calculated by subtracting the effective width of expansion joint from the summation of the expansion of the pavement section. The temperature change causing the effective expansion of pavement section was also calculated. The effective expansion equivalent temperature change was compared to the critical temperature, which causes the blowup, according to expansion joint spacing to verify the propriety of expansion joint applied to the airport concrete pavement. RESULTS : When an initial vertical displacement of the expansion joint was 3mm or less, the blowup never occurred for 300m of joint spacing which is used in Korean airports currently. But, there was a risk of blow-up when an initial vertical displacement of the expansion joint was 5mm or more due to the weather or material characteristics. CONCLUSIONS : It was confirmed that the intial vertical displacement at the expansion joint could be managed below 3mm from the previous research results. Accordingly it was concluded that the 300m of current expansion joint spacing of Korean airports could be used without blowup by controling the alkali-silica reaction below its allowable limit.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.25-35
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• 2012

PURPOSES : Hollows are easily made, and bearing capacity can be lowered near underground structures because sublayers of pavement settle for a long time due to difficult compaction at the position. If loadings are applied in this condition, distresses may occur in pavement and, as the result, its lifespan can decrease due to the stress larger than that expected in design phase. Although reinforced slab is installed on side of box culvert to minimize the distresses, length of the reinforced slab is fixed as 6m in Korea without any theoretical consideration. The purpose of this paper is investigating the behavior of concrete pavement according to the cover depth of the box culvert ad the length of the reinforced slab. METHODS : The distresses of concrete pavement slabs were investigated and cover depth was surveyed at position where the box culverts were located in expressways. The concrete pavements including the box culverts were modeled by finite element method and their behaviors according to the soil cover depth were analyzed. Wheel loading was applied after considering self weight of the pavement and temperature gradient of the concrete pavement slab at Yeojoo, Gyeonggi where a test road was located. After installing pavement joint at various positions, behavior of the pavement was analyzed by changing the soil cover depth and length of the reinforced slab. RESULTS : As the result, the tensile stress developed in the pavement slab according to the joint position, cover depth, and reinforced slab length was figured out. CONCLUSIONS : More reasonable and economic design of the concrete pavement including the box culvert is expected by the research results.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.47-55
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• 2013

PURPOSES : The purpose of this study is to investigate the optimal joint positions which can minimize distresses of concrete pavement containing box culvert with horizontally skewed angles. METHODS : The concrete pavement containing the box culvert with different skewed angles and soil cover depths was modeled by 3 dimensional finite element method. The contact boundary condition was used between concrete and soil structures in addition to the nonlinear material property of soil in the finite element model. A dynamic analysis was performed by applying the self weight of pavement, negative temperature gradient of slab, and moving vehicle load simultaneously. RESULTS : In case of zero skewed angle ($0^{\circ}$), the maximum tensile stress of slab was the lowest when the joint was positioned directly over side of box culvert. In case there was a skewed angle, the maximum tensile stress of slab was the lowest when the joint passed the intersection between side of the box culvert and longitudinal centerline of slab. The magnitude of the maximum tensile stress converged to a constant value regardless the joint position from 3m of soil cover depth at all of the horizontally skewed angles. CONCLUSIONS : More reasonable and accurate design of the concrete pavement containing the box culvert can be possible based on the research results.