• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.353-358
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• 2001

The cement concrete pavements are designed twenty years of performance life in Korea. At the present time, some expressways have been elapsed seventy percent of performance life which are detecting local failures. The most repair methods using to repair failures are partial depth repair and full section repair. These methods are most important bonding strength between rapid curing materials and substrate concrete pavements. This study was performed to evaluate bonding strength of the composites section made of rapid curing material and substrate concrete pavements. The pull-out tester was used to test bonding strength for the composites section made of each materials. In the results of the test, the bonding strength values of the epoxy mortar and acrylic mortar are higher than those of the other materials. The performance life of repaired section is affected by various factor. The bonding strength of bonded composites section may be affect the performance life, significantly.

• Advances in concrete construction
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• v.5 no.1
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• pp.1-15
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• 2017

This research project aimed at evaluating experimentally the effect of natural perlite powder as an alternative supplementary cementing material (SCM) on the performance of fiber reinforced self-consolidating repair mortars (FR-SCRMs). For this purpose, four FR-SCRMs mixes incorporating 0%, 10%, 20%, and 30% of natural perlite powder as cement replacements were prepared. The evaluation was based on fresh (slump flow, flow time, and unit weight), hardened (air-dry unit weight, compressive and flexural strengths, dynamic modulus of elasticity), and durability (water absorption test) performances. The results reveal that structural repair mortars confronting the performance requirements of class R4 materials (European Standard EN 1504-3) could be designed using 10%, 20%, and 30% of perlite powder as cement substitutions. Bonding results between repair mortars containing perlite powder and old concrete substrate investigated by the slant shear test showed good interlocking justifying the effectiveness of these produced mortars.

• Journal of the Korea Institute of Building Construction
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• v.19 no.4
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• pp.299-306
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• 2019

In general, repair mortar is used to rehabilitate underground communities, but difficulties are encountered in the execution of long-term construction due to spatial co-operatives. In this study, the engineering properties of repair mortar according to the curing condition and accelerator type were reviewed. The results showed that the aluminate, alkali-free and calcium-aluminate precipitates in the water curing conditions showed higher compressive strength at the beginning of age than mortar specimens under air curing conditions, and increased. Especially in CA and AF test specimen with cement mineral quick setting, a large amount of ettringite products were observed compared with AL, thus reducing the pore volume and increasing the strength of the compound by micro-filling effect were found.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.305-308
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• 2006

This paper is to investigate the strength, impact endurance and shrinkage of wet spraying type fiber composite mortar for repair material depending on fiber type and product kinds. Fiber composite mortar containing PVA fiber had the highest strength compared to that using any other fiber. Especially, The use of PVA fiber results in a remarkable enhancement in impact strength and an improved volumetric stability. Accordingly, it is confirmed that fiber composite mortar containing PVA fiber has remarkable performance as repair material of damaged section of concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.295-298
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• 2012

Repair and strengthening is necessary to extend the service life of existing buildings. Polymer-modified cement mortar (PCM) has been extensively used as a high performance material particularly for finishing and repairing works in concrete building because of itsexcellent adhesion, waterproofing, resistance to chemical attack, and workability. As PCM contains organic polymer, it is necessary to clarify its properties at high temperature under fire, on which sufficient data are not available. This paper evaluated the burn-up characteristics of polymer-modified cement mortar with cone calorimeter test, non-combustibility test and flammability test with experimental parameters such as the types of polymer, unit-polymer content, polymer-cement ratio and thickness of the specimen.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.401-404
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• 2005

Because the underwater structures are subjected to the deterioration according to use environment, it is necessary to repair and reinforce when the durable performance are considered in structures. Epoxy mortar in the underwater used to the repair and reinforcement for durability. Epoxy mortar in the underwater-harding maked epoxy and filler. Filler is divided aggregate and powder system. Because aggregate take a matter too seriously to supply that alternation material is used to rapidly chilled steel slag. As result of study, it is possible that rapidly chilled steel slag can be applied for replacement materials about aggregate in epoxy mortar because the strength is not different.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.281-284
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• 2005

This research is a study on development of section restoration mortar by multi-functional slag aggregate. Compressive strength, flexural strength and other physical properties on five standards are measured to obtain optimal addition rate (of multi-functional aggregate) and to investigate applicability of multi-functional aggregate in developing repair mortar. As the study result, the properties of repair mortar, such as compressive strength and flexural strength etc. are improved by addition of multi-functional aggregate and confirmed reduction effect of air content.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.409-412
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• 2005

Because the underwater structures are subjected to the deterioration according to use environment, it is necessary to repair and reinforce when the durable performances are considered in structures. In generally, epoxy mortar is used to repair materials of underwater concrete. It is divided epoxy and filler which is organized cement and sand. Cement can be replaced by stone powder sludge in waste because the grading of stone powder sludge in drying state has similar to that of cement. As result of study, it is possible that stone powder sludge can be applied for replacement materials of cement in epoxy mortar, because the strength is not different when filler in epoxy mortar is alternated stone powder sludge.

• Computers and Concrete
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• v.12 no.5
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• pp.651-668
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• 2013

Concrete structures need repairing due to various reasons such as deteriorative effects, overloading, poor quality of workmanship and design failures. Cement based repair mortars are the most widely used solutions for concrete repair applications. Various factors may affect the bond strength between concrete substrate and repair mortars. In this paper, the effects of polymer additives, strength of the concrete substrate, surface roughness, surface wetness and aging on the bond between concrete substrate and repair mortar has been investigated. Full factorial experimental design is employed to investigate the main and interaction effects of these factors on the bond strength. Analysis of variance (ANOVA) under design of experiments (DOE) in Minitab 14 Statistical Software is used for the analysis. Results showed that the interaction bond strength is higher when the application surface is wet and strength of the concrete substrate is comparatively high. According to the results obtained from the analysis, the most effective repair mortar additive in terms of bonding efficiency was styrene butadiene rubber (SBR) within the investigated polymers and test conditions. This bonding ability improvement can be attributed to the self-flowing ability, high flexural strength and comparatively low air content of SBR modified repair mortars. On the other hand, styrene acrylate rubber (SAR) modified mortars was found incompatible with the concrete substrate.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.167-172
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• 2017

In this study, high performance patching repair mortars with light weight and sulfuric acid resistance properties were suggested. Their performance estimation were investigated based on KS F 4042 using patching repair mortar with light weight aggregate and soluble polymer of Type I and sulfuric acid resistance mortar of Type II, From these results, it was confirmed that these motors were satisficed and improved by all standard tests of KS F 4042.