• Journal of the Korea Concrete Institute
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• v.23 no.3
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• pp.289-294
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• 2011

The installation of joint is to prevent random cracking due to drying shrinkage stress of concrete slab. However contraction joint spacing is empirically implemented into slab constructions without detail calculation based on quantitative criteria. In this study, shrinkage strain of concrete due to concrete shrinkage stress was measured to suggest joint spacing based on the study results. The test environmental conditions were applied temperature of $15^{\circ}C$ and relative humidity of 60%. The design compressive strength used was 30 MPa and 40 MPa, which are currently used in concrete slab designs. The drying shrinkage test result was applied to drying shrinkage models (ACI 209R, CEB MC 90, B3, GL 2000 and Sakata). The results showed that the most appropriate model was ACI 209R model. Based on the research findings, quantitative contraction joint spacing locations were calculated.

• Magazine of the Korea Concrete Institute
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• v.14 no.2
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• pp.77-82
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• 2002

일반적으로 공동주택 지하주차장과 같이 구조물이 대형화되거나 복잡할 경우 구조물의 응력취약 부위에서 균열, 누수 등의 문제가 발생할 확률이 크다. 이에 대한 대책으로 설계자들은 신축줄눈을 선호하고 있으나 신축줄눈은 시공상의 어려움과 사용 중 잦은 하자 발생이라는 문제점을 안고 있다. 이 때문에 근래에 들어 대형 건물을 한 단위로 처리하고 철근으로 보강하려는 경향이 있으나 구속도 차이에 따라 균열, 누수 등의 문제가 여전히 발생하고 있다. 이를 해결하기 위하여 수축대를 설치하여 일정 요구량의 초기 수축량을 수축대에서 흡수하고 이후 수축대 부위에 콘크리트를 메워 일체화시킴으로써 초기 수축에 의한 균열을 상당부분 방지할 수 있다.(중략)

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1D
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• pp.57-65
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• 2008

Joint of concrete pavement contributes to improvement of pavement performance by preventing occurrence of random cracking due to drying shrinkage and temperature changes of concrete slabs at early age. However, saw-cutting operations performed prior to sufficient concrete hardening develop micro-cracking of the concrete near the joints, which may develop to long-term distresses due to repetitious traffic and environmental loadings. To reduce the distresses, the joint crack inducers with heights of 100 mm, 150 mm, and 220 mm and the joint cracking slots with various depth were installed at a test section to investigate occurrence of the joint cracks and their behaviors over 5 months. As the results, higher efficiency of the crack inducing and larger behavior of the joint cracks were observed for the taller joint crack inducer. Higher efficiency of the crack inducing and improvement of the joint performance are warranted by additional investigation and reformation of the joint crack inducer.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.69-77
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• 2005

Joint spacing is a potent influence in increasing the long term performance of jointed concrete pavement slabs through the control of tensile stress, sealant failure and Load Transfer Efficiency (LTE). Internal Joint Spacing is an empirical and fixed method therefore this study will present the optimum joint spacing considerations depending on various climactic conditions. Calculating the optimum joint spacing eliminates random cracking due to the effect of the environmental loads such as the early behavior of drying shrinkage and heat hydration. Optimum joint spacing is calculated so as not to cause pavement distress by the deterioration of LTE by long term pavement movement. This study shows that the provisional joint spacing is 6-8m. Pavement Distress Prediction Models show that pavement distress has no effect on joint spacing of 8m.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.194-195
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• 2022

The jointing of unsupported concrete on the parking lot floor is a process for cracking and stress relief due to concrete drying shrinkage and restraint, but curling occurs due to long-term drying shrinkage after the initial age. will be lowered Therefore, by using an expansion material and a shrinkage reducing agent, the dry shrinkage of concrete is realized to 200 με or less.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.105-115
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• 2008

It is known that the long-term behavior and performance of jointed concrete pavement due to slab curling are affected by the environmental factors such as temperature, moisture, and so on. However, any relationships between the curling and its factors have not been defined clearly yet because of insufficient detailed investigation. The temperature, relative humidity, strain, vertical displacement of a concrete slab, and horizontal movement of its transverse joints were investigated by various sensors and devices instrumented in the slab of a concrete pavement section constructed for this study. The constraint of the curling by joint stiffness was investigated in addition to effect of the temperature and moisture on the early aged concrete slab by analyzing the field data measured for approximately 4days from concrete placement. The curling of the concrete slab showed 24hour cycles mainly because of the temperature effect, and the upward curling gradually increased because of the long-term effect of drying shrinkage of the concrete. The magnitude and variation of the curling were significantly affected by the joint stiffness which is comprised of aggregate interlocking and other factors. The effect of the variation of the seasonal joint stiffness varying with the temperature and long-term drying shrinkage on the slab curling will be investigated as a further study.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.133-139
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• 2009

Joints on concrete road prevent failure and crack securing the moderate space when concrete slab expands and contracts as a function of varying temperature throughout all seasons. Filling joint sealants in joints can prevent the interruption of slab movement and failure due to the infiltration of alien substances, and also can prevent crack caused by freezing and thawing and Dowel bar corrosion resulted from water - rainfall and snowfall infiltration through the inside the pavement. They lead to the improvement of the commonality of road. This paper evaluates physical strength, weatherability and deicer resistance of a two-year aged sample from joint on concrete road and its virgin sample. It was found that there are significant differences in aspects of weatherability and adhesive force between the tested sample and silicon materials.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.51-59
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• 2011

Tensile stress occurs and random crack develops in concrete pavement slab when it contracts by variation of temperature and humidity. The tensile stress decreases and the random crack is minimized by sawcutting the slab and inducing the crack with regular spacing. The random crack, joint damage, decrease of load transfer efficiency are caused by too wide joint spacing while too narrow joint spacing leads to increase of construction cost and decrease of comfort. A mechanistic-empirical joint spacing design method for the concrete pavement was developed in this study. Structurally and environmentally weakest sections were found among the sections showing good performance, and design strengths were determined by finite element analysis on the sections. The joint width for which the load transfer efficiency is suddenly lowered was determined as allowable joint with referring to existing research results. The maximum joint spacing for which the maximum tensile stress calculated by the finite element analysis did not exceed the design strength were found. And the maximum joint width expected by the maximum joint spacing were compared to the allowable joint width. The new method developed in this study was applied to two zones of Hamyang-Woolsan Expressway being designed. The same joint spacing as a test section constructed by 8.0m of joint spacing wider than usual was calculated by the design method. Very low cracking measured at 6 years after opening of the test section verified the design method developed in this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1091-1096
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• 1994

Since horizontal movements due to shrinkage and thermal gradients in concrete pavements involve no actual load, the stresses induced will be those due to closing of the pavement joints and subbase friction. Consequently, complete derivations of stiffness matrix and equivalent nodal loads due to planar effects on the concrete pavements was throughly undertaken using the finite rectangular elements with two degrees of freedom at each node. The numerical example shows that the tensile stress induced in a pavement due to concrete shrinkage might be negligible except at very long slab and very high coefficient of frictions. However the stresses in conjunction with principal traffic loads might cause cracking problems.

• Computational Structural Engineering
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• v.4 no.2
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• pp.95-102
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• 1991

Some sections of concrete highway pavements have been viewed with great concern by highway officials and engineers due to the severe cracking and failure problems. This is mainly due to the traffic loads in addition to temperature variations between top and bottom of concrete slab, which cause the concrete slab to curl up and down depending on the thermal gradient, respectively. Subsequently, a major consideration was given to the derivation of stiffness matrix and equivalent nodal loads due to the uniform gravity load, temperature and shrinkage of concrete. And the structural behavior of concrete highway pavement due to the temperature variations throughout the nations has been emphasized.