• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.5
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• pp.39-50
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• 2008

This study are decided the mix proportion method of latex modified concrete for agricultural concrete structures from the results of workability and strength test with mix proportion factor. For mix proportion factor, this study are selected the water-cement ratio, unit cement amount and latex content. Also, this study were performed the slump, compressive strength test and microstructure analysis using the scanning electron microscope(SEM). The strength and slump of LMC are dependent with unit cement amount, latex content, and water-cement ratio. Especially, the strength of LMC are not controlled by single mix proportion factor but effected by combined mix proportion factor. Microstructure investigation are showed the LMC are reduced the internal pore volume and enhanced the transition zone between cement paste and aggregate interface. This effect get by consist of latex films in the concrete. Also, this study were recommended the mix proportion method for LMC. These mix proportions method are estimated the mix design for satisfied the target performance which are applied the agricultural concrete structure.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.161-168
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• 2002

Latex modified concrete is governed by both cement hydration and polymer film formation processes in its binder phase. Such the reactions are expected to improve the polymer-cement co-matrixes themselves and the bond between the cement hydrates and aggregates, and to improve the properties of hardened latex-modified concrete. The purpose of this study was to study the strength and chemical resistance of Rapid-setting latex modified concrete(RSLMC) with the main experimental variables such as latex content(0, 5, 10, 15, 20%) and water-cement ratio(36, 38, 40%) at latex content 15%. Water absorption test was earned out to estimate water permeability resistance. Chemical resistance test was carried out to measure the weight change and to observe the appearance of RSLMC immersion in hydrochloric acid, sulfuric acid, and calcium choloride.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.475-480
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• 2003

Latex modification of concrete provides the material with higher flexural strength. This increase in flexural strength can attribute to the crack-arresting action of polymer in concrete, and also to the bonding they provide between the matrix and aggregates. This experimental study presents the fracture behavior of 12 flexural reinforced concrete beams repaired or strengthened by latex-modified concrete with the main experimental variables such as overlay thickness, strength thickness, and shear reinforcement. The results are as follow: All beam specimens having shear reinforcement were failed by delamination rupture at concrete interface at about 80% of ultimate loading after flexural cracking. All specimens overlayed and strengthened by latex-modified concrete (LMC) showed higher ultimate flexural strength than OPC control specimen, but lower than LMC control specimen. This increase in flexural strength could attribute to the high bonding they provide between the matrix and aggregates. All specimens except two shear unreinforced showed quite similar and consistent displacement behavior. The effect of overlay and strength thickness on the load-displacement relationship were a small at this study.

• 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 Korea Concrete Institute Conference
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• 2002.05a
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• pp.151-156
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• 2002

Drying shrinkage cracking which may be caused by the relatively large specific surface is a matter of grave concern for latex modified concrete(LMC) overlay and rapid-setting cement latex modified concrete(RSLMC) overlay. LMC and RSLMC were studied for field applications very actively in terms of strength and durability in Korea. However, there were no considerations in drying shrinkage. Therefore, the purpose of this study was to investigate the drying shrinkage properties of LMC and RSLMC with the main experimental variables such as cement types(ordinary portland cement, rapid setting cement), latex contents(0, 5, 10, 15, 20%), W-C ratios, and curing days at a controlled environment of 60% of relative humidity and 2$0^{\circ}C$ of temperature. The drying shrinkage for specimens was measured with a digital dial gauge of Demec. The test results showed that the drying shrinkage of LMC and RSLMC were considerably lower than that of OPC and RSC, respectively. This might be attributed to the interlocking of hydrated cement and aggregates by a film of latex particles, water retention due to hydrophobic, and colloidal properties of the latexes resulting in reduced water evaporation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.147-156
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• 2006

This study is purposed to improve the performance of concrete made of recycled coarse aggregate. For this, recycled aggregate concrete was produced with SBR latex, and fluidity, dynamic performance and drying shrinkage were examined. According to the result, with mixing 6% of SBR latex, fluidity having resistance against segregation can be insured and compressive and flexural strength was increased. Especially the increment in terms of flexures was remarkable. In addition to, with above mixing ratio, drying shrinkage was reduced. Therefore there is a strong inference that superior recycled aggregate concrete can be produced with using 6% of SBR latex.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.949-952
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• 2008

The latex modified concrete(LMC) was adds latex in the plain concrete as the latex has increase the durability of concrete. But it is added in LMC manufacture, which is a high price compares with different material and there is a weak point where the construction expense is very high. So, this study are decided mix proportion from the scope where the security strong point of LMC is possible and reduced the material expense by control the latex contents. and these mix proportions are estimated the chloride ion diffusion. The results of study appear that it can reduced the latex content until the $5{\sim}10$% of cements, and these mixtures are very low chloride ion diffusion.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.269-272
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• 2004

After concrete casts, temperature decent and shrinkage bring volume changes of concrete pavement. Microcracking and cracking in concrete pavement are caused by these volume changes. As a result, durability of concrete pavement is deteriorated. Recently, Very-Early Strength Latex Modified concrete(below:VESLMC) from the beginning of High-Way is used as urgent repair material for bridge deck. The advantage of VESLMC is that compressive and flexural strength at 3 hours age are 4.5MPa and 21MPa respectively. It allows the traffic to open in 3 hours. But, this material has the problem which is early-age shrinkage cracking caused by water self-dissipation with rapid hydration reaction and water evaporation with body dry. Unfortunately, until now, the research about early-age shrinkage of VESLMC leaves something to be desired. Therefore, the purpose of this study is to present the early-age shrinkage of VESLMC respect to latex contents and shrinkage ratio to maximum length change that can help field engineers' skill. Latex contents of 0, 5, 10, 15, $20\%$ in standard of same workability in VESLMC are selected by experimental variables. After initial set, shrinkage value was measured with 10mm LVDT for 3 days. The results of maximum shrinkage ratio were 0.019, 0.017, 0.023, $0.027\%$ respectively.

• 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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.247-252
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• 2009

The LMC method of construction which have application to the road bridge is being considered the least relative importance about the watertight performance, because it focused on the durability of concrete. However, The LMC which is being expanded scope of application to the method of construction has grown importance about the watertight performance on the usability and maintenance side as well as durability. In this study, The latex concrete of two types which are different from mingled-ratio of the latex made a comparison to the compressive strength, watertight performance, dynamic wheel load resistance performance and confirmed what it has resistibility about chemical action through the chemical resistance test. The initial strength and watertight performance showed that were tendency the downward at 14 days. However, The long-term strength after 28 days showed that it has firm performance. In consequence, The initial curing of latex concrete is required to scrupulous care and attention at the site application. As a chemical resistance test result, The specimen that is steeped in sulphuric acid solution of 2% discovered the delamination phenomenon. However, it was confirmed that delamination phenomenon don't have an effect on the compressive strength. Moreover, As a dynamic wheel load resistance test result, The latex concrete was concluded to confirming the durability and running stability, because it had hardly any thickness reduction of latex concrete surface about dynamic wheel load and rarely found crack and delamination.