• International Journal of Highway Engineering
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• v.12 no.4
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• pp.165-174
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• 2010

This study was conducted to evaluate the feasibility of expedite repairing of concrete pavements using precast concrete pavement method and to investigate the effectiveness of slab connection methods. In the demonstration construction, four slabs of jointed concrete pavements were replaced with the precast slabs. First, precast concrete slabs were designed and fabricated, then existing slabs were cut and removed, and finally precast slabs were installed. The slabs were leveled and pockets, holes, and space between the slab bottom and the underlying layer were grouted. From the demonstration construction, details about the design and construction of the precast pavements for repairing of pavements were evaluated. In addition, the slab connection methods such as pocket and hole connection methods were applied in the construction and the slab curling behaviors at the joints that include those connection methods were compared. The results showed that both slab connection methods were applicable, and the hole connection method was superior.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.69-76
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• 2020

Global warming is a very important problem as it causes rapid climate change and natural disasters. Therefore, researches related to renewable energy are being actively conducted while promoting policies such as reducing carbon dioxide emission and increasing the proportion of renewable energy. Solar power generation is being applied in urban areas like BIPV as well as existing idle areas outside the city. Therefore, in this study, precast concrete blocks developed for paving roadways capable of solar power generation were designed and constructed. For the evaluation of field applicability for 6 months, skid resistance and block settlement were measured. As a result of the experiment, it was found that skid resistance satisfies the standard of general roadway in Korea, but not the standard of highway. The skid resistance tended to decrease as time passed. In addition, the settlement of the block gradually increased slightly, but it is much smaller than the allowable settlement of the roadway. Therefore, it is necessary to establish a maintenance period and method based on the periodic measurement results in the future.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.337-340
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• 2008

The important factors that should be considered when designing and constructing the precast prestressed concrete pavement were investigated in this study. Those factors included traffic and environmental loads, interaction between the concrete slab and the underlying layers, determination of the slab thickness and the prestressing amount. In addition, the behaviors of the precast prestressed concrete pavement when post-tensioning was applied were analyzed using a finite element model. The effects of the number of anchors, the horizontal resistance of underlying layers, the pavement length, the slab thickness, and the bearing area of the anchorage on the distribution of compressive stresses were analyzed.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.491-498
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• 2012

This study examines setting shrinkage, coefficient of thermal expansion, and elastic modulus of unsaturated polyester( UP)-methyl methacrylate(MMA) polymer concrete, which is generally used for repair of portland cement concrete pavement and manufacturing of precast products. In this study, a series of laboratory test were conducted with variables such as UP-MMA ratio, shrinkage reducing agent (SRA) content, and test temperature. The results showed that the setting shrinkage ranged from 29.2 to $82.6{\times}10^{-4}$, which was significantly affected by test temperature. Moreover, the findings revealed that the coefficient of thermal expansion, elastic modulus and ultimate strain of UP-MMA based polymer concrete ranged from 21.6 to $31.2{\times}10^{-6}/^{\circ}C$, 2.8 to $3.3{\times}10^4$ MPa, and 0.00381 to 0.00418, respectively. The results of this study will be used as important data for design and application of UP-MMA based polymer concrete.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.388-395
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• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.