• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.4
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• pp.35-41
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• 2007

The most agricultural concrete structures for the irrigation and drainage are exposed to the underwater condition at the irrigation period and they take the influence on very severe cold in the winter. Therefore, it is impossible to use repair materials used to the general concrete structures. The research need the development of the repair material for a performance enhance of the agricultural underwater concrete structures. This research evaluated the mechanical and durability performance of the latex modified repair mortar for underwater concrete structures which peformed the repair in the underwater according to the characteristic of the agricultural concrete structure. The latex modified repair mortar is a material that minimize the effect of the ecosystem, environment and the segregation. In this research, the construction condition of the latex modified repair mortar for agricultural concrete structures was considered and the test specimens made in the underwater condition. Test results was then compared with target performance and commercial repair mortar. Experimental test results indicated that the mechanical and durability performance of latex modified repair mortar for agricultural underwater concrete structure satisfied all target performance. Also, the latex modified repair mortar resulted in better repair performance than the commercial repair mortar.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.93-99
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• 2013

Shotcrete has been referred to as gunite, pneumatically applied mortar or concrete, sprayed concrete or mortar. There are sound reasons why sprayed mortar is one of the best portland cement based material for repairing old concrete structures. However, it is difficult to find the research results on the latex-modified mortar nevertheless on the impact of air onto the fresh and hardened properties of latex-modified mortar. So, the main experimental program included strength test, slump test, rapid chloride permeability test, image analysis for air void system, and chemical attacks with the main experimental variables of latex content, fine aggregate content, water-cement ratio, and air foamer content.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.2
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• pp.37-46
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• 2007

The service life of agricultural concrete structures is designed in about 30 to 100 years, but actual service lift is estimated in an average 18 years. Therefore, as the service life of the agricultural concrete structures increases, necessity of repair by aging from various environment condition exposure increases. This study was to determinate the optimum mix proportion of latex modified repair mortar and to improve the durability performance of agricultural concrete structures. The physical and mechanical tests of latex modified repair mortar were performed. Tests of flow, compressive strength, flexural strength and bond strength tests were conducted. Test results show that the optimum nex proportion of latex modified repair mortar, when used in 5% latex volume fraction (weight of cement), 1.5% antifoaming agent (weight of latex), 0.2% PVA fiber volume fraction, 1:2 (binder-sand ratio), 10% silica fume replacement ratio (weight of cement), could result in best performance for the repair of agricultural concrete structures.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.3
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• pp.43-50
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• 2007

The purpose of this study was to determine the optimum mix proportion of latex modified mortar for agricultural underwater concrete structures repair. The experimental variables included a latex and antiwashout admixture amount, binder-sand ratio, water-binder ratio. This study were evaluated a repair performance and environment effect of latex modified repair mortar for agricultural underwater concrete structures. The pH test was conducted to evaluated the environmental effect and the flow test was peformed to evaluated the workability. Also, compressive, flexural and bond tests were conducted. Test results show that the optimum mix proportion of latex modified repair mortar for agricultural underwater concrete structures, was achieved by 1:1.5 binder-sand ratio, 5% latex ratio (weight of binder), 1.3% antiwashout admixture ratio (weight of binder), 0.33 water-binder ratio and 10% silica lune replacement ratio (weight of cement). The environmental effect and repair performance of optimum mix proportion satisfied all target performance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.179-182
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• 2009

Concrete containing styrene-butadiene latex is widely used, nowadays, as a protective system for bridge. Latex modification mortar have taken advantage of latex modification concrete advantage that is used in existing, Also, when repair, protection and sticking performance of concrete overlay waterproof agent were known as that are good. Replace and experimented from fine aggregate to recycled aggregate to secure economic performance than existing latex modification concrete. Recycled fine aggregate has low quality because it contains large amount of old mortar. So, its usage is limited to a lower value-add, such as the roadbed material etc. This study is purposed to improve the performance of mortar made of recycled fine aggregate. For this, recycled aggregate mortar was produced with latex, and fluidity, strength were examined. Test result indicate that mortar using recycled fine aggregate is higher compressive and flexural strength than mortar using river sand.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.5
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• pp.23-30
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• 2007

This research was to evaluate the shrinkage and durability performance of latex modified repair mortar and to improve the service lift of the agricultural concrete structures. The shrinkage characteristics of the repair material creates the delamination of repair materials and existing concrete. It may reduce the service life of structures. Also the reduction of durability performance of the repair materials induces the destruction of the repaired concrete structures at early stage. In this research, plastic and drying shrinkage, thermal expansion coefficient for shrinkage properties, durability performance, permeability, repeated freezing and thawing, and resistance of chemical solution test were performed. Test results showed that the latex modified repair mortar indicated the shrinkage amount which the delamination does not happen, and the latex modified repair mortar appeared excellent long-term durability performance which can increase the service life.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.633-636
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• 2008

Concrete structures are occur many various deteriorations in the course of time and many efforts have progressed to improve on performance of concrete. The purpose of this study is to evaluate the durability of latex modified mortar in order to repair concrete structure which are happened deterioration. In this study, we tested plastic shrinkage, drying shirnkage, repeated freezing and thawing, permeability and resistance of chemical solution. Latex modified mortar and two kinds of sprayed polymer mortar used on durability test. As a result of test, latex modified repair mortar was exhibited durablilty improvement compared to the conventional sprayed polymer mortars. It is judged the fact that latex modified mortar have no problem in site application but additionally many research will be necessary.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.5
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• pp.25-34
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• 2012

It has been well known that concrete structures exposed to acid and sulfate environments such as sewer etc. show significant decrease in their durability due to chemical attack. Such deleterious acid and sulfate attacks lead to expansion and cracking in concrete, and thus, eventually result in damage to cement mortar by forming expansive hydration products due to the reaction between cement hydration products and acid and sulfate ions. In this study, the effect of fly ash and blast furnace slag on the bond performances of structural synthetic fiber in latex modified cement mortar under sulfate environments. Fly ash and blast furnace slag contents ranging from 0 % to 20 % are used in the mix proportions. The latex modified cement mortar specimens were immersed in fresh water, 8 % sodium sulfate ($Na_2SO_4$) solutions for 28 and 50 days, respectively. Pullout tests are conducted to measure the bond performance of structural synthetic fiber from latex modified cement mortar after sulfate environments exposure. Test results are found that the incorporation of fly ash and blast furnace slag can effectively enhance the PVA fiber-latex modified cement mortar interfacial bond properties (bond behavior, bond strength and interface toughness) after sulfate environments exposure. The microstructural observation confirms the findings on the interface bond mechanism drawn from the fiber pullout test results under sulfate environments.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.249-256
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• 2001

The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as a basic experiments for RSLMC with the main experimental variables such as antifiamer types(A, B, C, D), antifoamer contents(0, 1, 2, 3%), and latex contents(10, 15%). Air content test and compressive strength tests were carried out to measure the improved properties of RSLMM. SEM analysis, also, was carried to observe the formation of latex film. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing an antifoam agent by 1%. This made the strength enhanced and the workability be within the purposed. The best properties of compressive strengths was obtained at latex content of 15% and D antifoam agent of 1%. compressive strength increased about 32.6%. The analysis of SEM results no difference in a formation of later film.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.51-57
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• 1996

The purpose of this study is to improve the properties by increasing of the adhesion strength of styrene-butadiene rubber(SBR) latex coated powdered rubber in cement mortar. SBR-modified mortar using powdered rubber is also tested as the same method. From the test results, the cement mortar using SBR latex coated powdered rubber have a good mechanical properties compared with that using uncoated powdered rubber. The mechanical properties of SBR-modified mortar using powdered rubber with polymer-cement ratios of 10% are also improved.