• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.732-737
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• 2016

Using the pyrolyzed carbon black (PCB) from waste tires, the performance of 13 mm dense-graded hot mix asphalt was evaluated. The Marshall mix design was carried out and the measured optimal asphalt content was 5.8%. The impact resonant test was conducted to obtain the elastic modulus and damping ratio of the hot mix asphalt. The elastic modulus of HMA increased with increasing amount of PCB. On the other hand, there was no significant change in the damping ratio. The Marshall mix design, indirect tensile test, permanent deformation test, and program analysis were carried out. The strength ratio of the PCB modified asphalt mixtures was within 10%. More 10% of PCB was not good for the permanent deformation of hot mix asphalt. From the pavement design program, the use of 5% PCB in hot mix asphalt showed a decrease in the top-down crack, bottom-up crack, and permanent deformation. Judging from the limited test and analysis, the use of 5% PCB is good for enhancing the pavement performance.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.5
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• pp.1-10
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• 2007

A laboratory investigation is conducted to characterize and quantify fatigue lives of continuously reinforced concrete pavements (CRCP) with initial design parameters. Eight specimens scaled were made based on results of finite-element analyses and stress-strain curve comparisons. Static tests were firstly performed to obtain magnitudes of static failure loads and to predict crack patterns before fatigue tests. The fatigue lives measured in the study were compared based on each initial design parameter. The comparison indicates that the fatigue lives of CRCP specimens with initial cracks increases with increasing the initial crack spacing, and CRCP specimens with reinforcements at top of the concrete slab have more fatigue lives than those with reinforcements at midheight of the concrete slab. In addition, the fatigue lives were significantly affected by soil conditions under the CRCP specimens. The results obtained in the study can be used for maintenance and retrofit of the continuously reinforced concrete pavements.

• The Journal of Society for e-Business Studies
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• v.26 no.1
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• pp.93-106
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• 2021

Many recent studies on deep learning-based road crack detection have shown significantly more improved performances than previous works using algorithm-based conventional approaches. However, many deep learning-based studies are still focused on classifying the types of cracks. The classification of crack types is highly anticipated in that it can improve the crack detection process, which is currently relying on manual intervention. However, it is essential to calculate the severity of the cracks as well as identifying the type of cracks in actual pavement maintenance planning, but studies related to road crack detection have not progressed enough to automated calculation of the severity of cracks. In order to calculate the severity of the crack, the type of crack and the area of the crack in the image must be identified together. This study deals with a method of using Mobilenet-SSD that is deep learning-based object detection techniques to effectively automate the simultaneous detection of crack types and crack areas. To improve the accuracy of object-detection for road cracks, several experiments were conducted to combine the U-Net for automatic segmentation of input image and object-detection model, and the results were summarized. As a result, image masking with U-Net is able to maximize object-detection performance with 0.9315 mAP value. While referring the results of this study, it is expected that the automation of the crack detection functionality on pave management system can be further enhanced.

• 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.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.2
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• pp.47-56
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• 2015

At the present, the mechanized form roads pavement was constructed with plain concrete. Mostly, it was used by welded wire mesh for preventing crack. Cellulose fibers for the reinforcement of concrete offer relatively high levels of elastic modulus, fiber count (per unit weight), specific surface, and bond strength to cement-based materials. The construction of concrete pavement confirmed that cellulose fiber reinforced concrete was applicable to mechanized form roads pavement. In the study, cellulose fibers were used here at 0.08 % volume fraction, which is equivalent to a fiber content of $1.2kg/m^3$. Cellulose fiber reinforced concrete were compared with plain concrete. Field test results indicated that cellulose fiber reinforced concrete showed slightly to increase of 28 days compressive strength and improved the initial strength. it tended to increase of splitting tensile strength. Test results showed that the slump and air content tend to decreased. but, the variation of air contends is very little. Also, construction cost of cellulose fiber reinforced concrete is less than about 25.7 % the case of welded wire mesh previously used. Therefore, The cost reduction is expected to be possible in construction site by mechanized form roads pavement.

• International Journal of Highway Engineering
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• v.14 no.6
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• pp.1-11
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• 2012

PURPOSES : The purpose of the study was to examine dynamic features of concrete after mixing a little macro fiber with small aspect ratio and long length utilized for bridge, tunnel and shotcrete for tensile performance and crack control in domestic/overseas countries with cement concrete pavement mix. METHODS : Coarse aggregates with small aspect ratio and macro fibers with maximum length of approximately 32 mm are introduced in small quantities in the mix proportions of concrete pavement so as to prevent loss of the workability. Then, this study intends to evaluate the applicability of macro fibers in the mix proportions of concrete pavement by examining the basic construction performance, as well as the change of toughness, the equivalent bending strength and the flexural toughness index caused by compression, bending, tension and the flexural stress-displacement curve. RESULTS : As the results, in each kind of macro fiber, polyvinyl alcohol fiber and steel fiber displayed a good performance. CONCLUSIONS : In 0.2 and 0.3% of fiber contents, it is appeared that polyvinyl alcohol fiber has a large effect on improvement of tensile performance and steel fiber on improvement of deforming performance of bending stress.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.165-173
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• 2003

The purpose of this paper is to analysis of initial behavior of concrete pavement with initial measurement strain gauge for concrete pavement at field, and to investigate the field test results for field applicability testing. The early-age behaviors of concrete pavement slabs were measured using the strain gauges. From the slab depths and positions, the outputs from each gauges were recorded at initial curing period. The initial measurement of concrete pavement and check of crack at the joint were performed, the results could be summarized as follows. From the results of concrete strength, compressive strength and flexural strength were showed $271kgf/cm^2$, $43kgf/cm^2$ respectively. From the tests of early-age strain measurement, it was found that the strain varied at the maximum value of $150{\mu}{\varepsilon}$ and early behavior of concrete slab was showed a tensile strain. However, for long-term was showed a compressive strain due to dry-shrinkage.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.571-579
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• 2016

RS-LMC (Rapid Setting Latex Modified Concrete) has been widely used as repair material for bridge deck overlay or rehabilitation, because the overlaid pavement could be opened to the traffic after 3 hours of curing. Although the field performance of RS-LMC generally indicates that it has an excellent bonding to the substrate and shows a long term performance, the crack by vibration of vehicles have been happened on the overlay of bridges in technical reports. In this study, experimental research was carried out to evaluate the vibration properties of RS-LMC overlays by using P.S.T (Pavement Shaking Table). Total 12 specimens were tested and the variables are Latex-cement ratio (L/C) and amplitude of vibration. The result shows that the number of cracks and the total length of cracks are reduced as the increase of Latex-cement ratio (L/C) until 15%. And the crack occurs at a very small strain than the proposed values by Walter, D, G and design codes.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.247-256
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• 2009

This research was conducted to analyze the behavior of PTCP (Post-Tensioned prestressed Concrete Pavement) under tensioning by performing field tests when the experimental PTCP slab was being constructed. The displacements in the slab under the environmental loading and tensioning were measured using temperature measurement sensors and displacement transducers. Tensioning was performed three times and appropriateness of tensioning could be determined by investigating the relationship between temperature and displacement, behavior of transverse crack, and daily change in displacement. The results of this study showed that under the first tensioning at very early age, large displacements were observed only near the joints because of the friction between slab and underlying layer and concrete inelasticity. Under consecutive tensioning, displacements were clearly observed all over the slab, but still affected by the friction. In addition, appropriate tensioning ensured the one-slab behavior of the PTCP slab even though cracks existed.

• International Journal of Highway Engineering
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• v.6 no.4 s.22
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• pp.75-89
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• 2004

Long term performance of concrete pavement significantly depends on the given construction and environmental condition. It means that random cracks and extreme crack width due to inappropriate quality control at the early age might lead to decreasing the pavement service life. The temperature and moisture during the construction, cement and aggregate types, curing condition are major components to affect the quality of the concrete pavement at the early age. First of all, the high temperature differential, that is made by increasing air temperature and the heat of cement hydration, is known as the major contributor to severe cracks. In this study, tent covering was used for controlling temperature of the concrete slab. The field measurement data indicates that the effect of the tent covering is very significant to decrease possibilities of random crack occurrence and curling stress and enhance the long-term concrete strength. HIPERPAV(High PERformance PAVing software), a program predicting the strength and stress of an earty-age concrete pavement (72 hour after placement), is used for simulating the effects of tent covering. The HIPERPAVE results showed that the section with the tent covering has higher reliability than the section without the tent covering by 22.5%. In details, reliability is increased 72.5% (without the tent covering) to 95% (with the tent covering).