• Journal of the Korea Institute of Building Construction
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• v.9 no.5
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• pp.71-77
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• 2009

In a range of forms, such as latex, water-soluble polymer, liquid resin, and monomer, polymer dispersions have been widely used in the construction industry as cement modifiers because of their excellent properties, such as acid-resistance, water-proofness, and good ductility in mortar and concrete. Polymer cement slurry (polymer-modified slurry) is made of cement and polymer dispersions, with a high polymer-cement ratio of 50% or more. The purpose of this study is to evaluate the water permeability and drying shrinkage of polymer cement mortar (polymer-modified mortar) and cement concrete coated by polymer cement slurry. The polymer cement mortar and cement concrete are prepared with various polymer types, polymer-cement ratios and curing methods, and are tested for water permeability, drying shrinkage and strength. The test results showed thatthe weight of permeable water of polymer cement mortar decreases with an increase in the polymer-cement ratio, reaching a minimum at the polymer-cement ratio of 20%. In particular, the weight of permeable water of St/BA-modified mortar with a polymer-cement ratio of 20% coated with St/BA-modified slurry is about 1/55 that of unmodified mortar. The EVA- and St/BA-modified slurries coated on cement concrete have about 4 or 5 times higher drying shrinkage compared to cement concrete. The strength of polymer cement mortars tends to increase with a higher polymer-cement ratio, and is considerably higher than that of unmodified mortar. It is thus concluded that polymer cement mortars coated by polymer cement slurry are effective for industrial application, and have superior properties such as waterproofness and strengths, compared with conventional cement mortar.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.979-984
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• 1997

Test specimens of polymer-cement concrete composites were prepared using styrene-butadiene rubber(SBR) latex, ethylenevinyl acetate(EVA) and polyacrylic ester(PAE) emulsions as polymer dispersions in cement modified system at constant slump($10{\pm}0.5cm$), then compressive and flexural strengths water absorption, pore size distribution, and microstructures were investigated. Compressive and flexural strengths of these composites were remarkably improved with an increase of polymer-cement ratio. These composites had a desirable pore size distribution against frost damage due to a small capillary pore volume. Continuous polymer film was able to form in higher than 15% of polymer cement ratio.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.559-567
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• 2005

The objective of this study is to optimize the use of mineral admixtures (silica fume, fly ash, and blast furnace slag) in high-performance concrete for bridge deck overlay. For this purpose, high-performance concrete, incorporating mineral admixtures, was tested for compressive strength and permeability. The Box Behnken design was used to determine the optimum mix proportions of the mineral admixtures. The optimized mix compositions were then technically evaluated. Test results are compare with the performance specification for high performance concrete overlay on bridge deck. The optimum mix proportions were shown to possess acceptable properties. Also, it is possible to save the construction and materials costs result from a reduction In actual material cost and from the use of widely avaliable truck mixers instead of mobile mixers.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.81-89
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• 2013

PURPOSES : This study is to evaluate ASR(alkali silica reactivity) resistance of ternary blended binder adding ultra fine mineral admixture. METHODS : This study analyzes ASR expansion using ASTM C 1260 and 1567. RESULTS : This study showed that the fineness of mineral admixture had no effect on ASR expansion. The expansion of ternary blended binder(UFFA 20%+FGGBS 10%) were below 0.1%, and this binder met the ASR standard. Also when adding the CSA expansion agent, ASR expansion slightly decreased. The expansion of latex modified mixture increased by 80% comparing plain mixture. CONCLUSIONS : Ternary blended binder met the ASR standard, and this binder is available in concrete bridge deck overlay.

• Journal of the Korea Concrete Institute
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• v.14 no.2
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• pp.190-198
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• 2002

In this research the physical properties of polymer modified mortar containing pulverized FRP(Fiber-Reinforced Plastics) wastes fine powder as a part of fine aggregate were investigated. Styrene-butadiene rubber(SBR) latex, polyacrylic ester(PAE) emulsion and ethylene-vinyl acetate(EVA) emulsion were used as Polymer modifier. Polymer modified mortars containing FRP wastes fine powder were prepared with various FRP wastes fine powder replacement(5∼30 wt％) for fine aggregate and polymer-cement ratios(5∼20 wt％). The water-cement ratio, water absorption rates and hot water immersion test, compressive and flexural strengths of polymer modified mortars were tested and the results compared to those of ordinary portland cement mortar. As the results, compressive and flexural strengths of polymer modified mortar containing FRP wastes fine powder depend on the contents of FRP wastes fine powder, type and additional amounts of polymer modifier. Some of them showed higher compressive and flexural strengths than those of ordinary portland cement mortar. Especially, SBR-modified mortar showed the highest strengths properties among three types of polymer modifier. Also water absorption rates, compressive and flexural strengths of SBR-modified mortar were more superior than those of PAE or EVA-modified mortar. The optimum mix proportions of SBR-modified mortar was 20 wt％ of polymer-cement ratio and 20 wt％ of FRP wastes fine powder replacement. Otherwise heat cured polymer modified mortar accelerated the improvement of early compressive and flexural strengths.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.2
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• pp.124-134
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• 2013

This study investigated the effect of surface water on concrete substrate on adhesive strength in tension of very high flowable SBR-modified cement mortar. The specimens were prepared with proportionally mixing SBR latex, ordinary portland cement, silica sand, superplasticizer and viscosity enhancing agent. Polymer cement ratio (P/C) were 10, 20, 30, 50 and 75% and the weight ratio of fine aggregate to cement were 1:1 and 1:3. The specimens obtained with different P/C and C:F were characterized by unit weight, flow test, crack resistance and adhesion test. After basic tests, two mixtures of P/C=20% and 30% in case of C:F=1:1, and one mixture of P/C=50% in case of C:F=1:3 were selected, respectively. These three selected specimens were studied about the effect of surface water evenly sprayed on concrete substrate by a amount of 0, 0.006, 0.012, 0.017, 0.024g per unit area ($cm^2$) of concrete substrate surface The results show that surface water on concrete substrate increases the adhesive strength in tension of high flowable SBR-modified cement mortar and improve the flowability compared to the non-sprayed case.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.129-137
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• 2017

PURPOSES : The purpose of this study is to develop bridge deck concrete materials based on ordinary Portland cement concrete, and to evaluate the applicability of the developed materials through material properties tests. METHODS : For field implementation, raw material (cement, fine aggregate, and coarse aggregate) properties, fresh concrete properties (slump and air content), strength (compressive, flexural and bond strength) gain, and durability (freeze-thaw resistance, scaling resistance, and rapid chloride penetrating resistance) performance were evaluated in the laboratory. RESULTS : For the selected binder content of $410kg/m^3$, W/B = 0.42, and S/a = 0.48, the following material performance results were obtained. Considering the capacity of the deck finisher, a minimum slump of 150 mm was required. At least 6 % of air content was obtained to resist freeze-thaw damage. In terms of strength, 51.28 MPa of compressive strength, 7.41 MPa of flexural strength, and 2.56 MPa of bond strength at 28 days after construction were obtained. A total of 94.9 % of the relative dynamic modulus of elasticity after 300 cycles of freeze-thaw resistance testing and $0.0056kg/m^2$ of weight loss in a scaling resistance test were measured. However, in a chloride ion penetration resistance test, the result of 3,356 Coulomb, which exceeds the threshold value of the standard specification (1000 Coulomb at 56 days) was observed. CONCLUSIONS : Instead of using high-performance modified bridge deck materials such as latex or silica fume, we developed an optimum mix design based on ordinary Portland cement concrete. A test construction was carried out at ramp bridge B (bridge length = 111 m) in Gim Jai City. Immediately after the concrete was poured, the curing compound was applied, and then wet mat curing was applied for 28 days. Considering the fact that cracks did not occur during the monitoring period, the applicability of the developed material is considered to be high.

• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.587-596
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• 2011

Ultra rapid-hardening cement is widely used for latex-modified mortar and concrete as repair and finishing material during urgent work. The purpose of this study is to evaluate the improvements in strength made to SBR cement mortars by the adding of various admixtures and by the use of different curing methods. SBR cement mortar was prepared with various polymer-cement ratios, curing conditions and admixture contents, and tested for flow, flexural and compressive strengths. From the test results, it was determined that the flow of SBR cement mortar increased with an increase in the polymer-cement ratio, and the water reducing ratio also increased. The strength of cement mortar is improved by using SBR emulsion, and is strengthened by adding metakaoline. The strength of SBR cement mortar cured in standard conditions was increased with an increase in the polymer-cement ratio, and attained the maximum strengths at polymer-cement ratios of 15 % and 10 %, respectively. The maximum strengths of SBR cement mortar are about 1.8 and 1.3 times the strengths of plain mortar, respectively. In this study, it is confirmed that the polymer-cement ratio and curing method are important factors for improving the strengths of rapid-hardening SBR cement mortar.