• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.387-392
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• 1994

Recently, as the problems according to lack of skilled labour and superior construction materials were gathering strength, there were required the advent of a special materials in building construction division. As a view of the point, the cement-based Self leveling mortar was developed for improvements of the former problems. The Self leveling mortar has the all kinds of the properties as followed the premixed products in plant, self-smoofhing, non shrinkgae etc, accordingly the finishing of concrete floor don't need skilled labour. The purpose of this study is to establish the introduction of a finishing construction method for concrete floor and slab using the cement-based self leveling mortar. Presented is a study on the basic properties of fresh and hardened self leveling mortar. To this end, an actual floor's finishing construction using the cement-based self leveling mortar was conducted in approximately 1,800㎡ floor as to compare the flatness and levelness after finighing.

• Computers and Concrete
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• v.5 no.2
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• pp.89-100
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• 2008

This research examines the engineering properties and color intensities of mortar containing different amounts of fly ash (0, 5, 10 and 20%) mixed at different water-to-binder ratios (w/b = 0.23, 0.47 and 0.59) and exposed at different temperatures (T = 25, 100, 200, 400, 600 and $800^{\circ}C$). Results show that there is greater mass loss on ignition with high w/b and higher temperatures. In addition, the color channel image analyzer (Windows software written in Delphi) is utilized to study the relationship between the curing temperature and intensity of three primary colors, red, green and blue (RGB), of the fly ash mortar specimens. The results show that the RGB intensities on the specimen surface increases from that at $25^{\circ}C$. The mortar specimen becomes white with increase in w/b but without the addition of fly ash. Moreover, for mortar specimens with greater content of fly ash, red on the specimen surface has the greatest increase in intensity at elevated temperature. Observation the variations in color on the specimen surface may help estimate the highest elevated temperatures that concrete structures can withstand.

• Journal of the Korea Concrete Institute
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• v.11 no.6
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• pp.121-128
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• 1999

The SHO PATCH System Mortar is a mortar shotcreting system which uses fairly small machine and equipment, and is applied for shotcrete tunnel linings, in particular for small bore tunnels of aqueducts by the TBM(Tunnel Boring Machine) method, and for reparing tunnels suffering from spring water and deterioration. This study shows the characteristics of the new mortar shotcreting system, the SHOT PATCh System Mortar, which exhibits excellent shotcrete performance.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.107-112
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• 1998

The objective of this study was to develop a polymer mortar defensive block with high strength and durability using unsaturated polyester resin to complement defects of conventional cement mortar defensive block. Physical and mechanical properties of the polymer mortar defensive block were also investigated. Low absorptivity, high impact strength, and great bending strength of the polymer mortar defensive block was compared with those of the conventional cement defensive block. In conclusion, the polymer mortar defensive block is excellent and useful as industrial products for erosion control works.

• Journal of the Korea Concrete Institute
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• v.15 no.5
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• pp.739-746
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• 2003

Various researches on the application of polymer dispersions to the cement mortar and concrete have been carried out in many countries like America, Japan and Germany and so on due to their high performance and good modification effect. PAE of polymer dispersion widely used in situ was employed that the high flowability may be induced in the cement mortar. In order to investigate the modification of cement mortar with high flowability by PAE and fracture mode of adhesive strength properties in tension of that, experimental parameters were set as PAE solid-cement ratio(P/C) and cement: fine aggregate(C:F) and the experiments such as unit weight, flow, consistency change, crack resistance and segregation that inform on the general properties have been done. Adhesion in tension is measured with a view to comprehending the properties and fracture mode in tensile load. Consistency change of cement mortar modified by PAE did grow better as the ratio of PAE solid-cement increased and was much superior to that of resin based flooring such as polyurethane and epoxy which recorded the loss of consistency in 90 min. after mixing. Adhesive strength in tension increased with continuity during curing period and showed the maximum in case of C:F=1:1 and P/C=20%.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1273-1278
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• 2007

The cement-asphalt mortar is a mixture of cement and asphalt emulsion, and is utilized as a underpouring materials for the railway track which is used to fill under slab panel space so as to provide a stabilized track support and a tool for reduction of noise and vibration. To increase the workability of grouting, this study investigates the effect of temperature on cement-asphalt mortar by analyzing its physical and mechanical properties before/after hardening according to the temperature (10, 15, 20, 25, $30^{\circ}C$). According to the test results, it is found that as for the physical property of fresh cement-asphalt mortar the more mixture temperature become higher or lower, the more fluidity become worse. But by increasing reducing agent amount and its unit quantity, the required fluidity is met. The compressive strength as physical property of hardened cement-asphalt mortar become lower when temperature is lower but taking it by and large the physical properties of cement-asphalt mortar before/after hardening aren't so affected by temperature and well satisfy the requirement. And it has proved that rate of expansion and freezing and thawing resistance aren't affected by temperature.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.793-796
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• 2004

In domestic, various repair materials and method systems to keep up with these reinforced concrete deteriorated due to salt damage, carbonation. chemical decay et. being developed and applied. However, present polymer cement mortar applied to section restoration system cause the problem of long-term working and economica] efficiency. because that is divided into two process of liquid corrosion prevention agent and polymer cement mortar. In this background, accelerated test with due regard to $3\%$ NaCl soaking and autoclave cure was performed to confirm steel bar corrosion prevention properties of polymer cement mortar mixed with corrosion prevention agent of powdered type. In conclusion. we confirmed application possibility and excellency of steel bar corrosion prevention properties of polymer cement mortar mixed with corrosion prevention agent of powdered type comparing general polymer cement mortar applied to section restoration system of present study.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.211-214
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• 2005

Recently, Deterioration of the concrete sewer concrete structures by biochemical corrosion has been issued and a development of the inhibition system of corrosion that has been demanded. The sulfuric acid may react with the hardened cement paste and originate expansive products which can induce swelling and breakless of concrete. Also, a sulphuric acid reacts with calcium hydroxide to from $CaSO_4\;\cdot\;2H_2O$. This reaction accounts for consumption of the calcium hydroxide present in hardened cement paste. In this study, To present from biochemical corrosion of the sewer repair mortar that was spread with liquefied antibiotic and then its experimental properties were experimentally investigated and to estimate the effect of absorbed condition of restorative mortar, the number of coating times and coating contents with antibiotic on the durability properties of restorative mortar spread with antibiotics. Also, testing items such as carbonation depth, choloride ion penetration depth and chemical resistance was tested to estimate the durability properties in third study. In results, the novellus bacillus inhabiting in sewer concrete structures was restrained by antibiotics developed in this study. And carbonation depth, choloride ion penetration depth and chemical resistance of restorative mortar spread with antibiotics was superior to that of plain mortar.

• Journal of the Korean Society of Safety
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• v.23 no.3
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• pp.51-57
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• 2008

NDT(Non-Destructive Testing Evaluation) using electromagnetic(EM) properties can be used for evaluation of physical performance in cement-based materials. In this study, a technique for strength evaluation in cement mortar is proposed through the measured EM properties(conductivity and dielectric constant). For this research, cement mortar specimens with 5 W/C ratios are made for evaluation of compressive strength and they are also utilized for tests of EM properties in the range of $0.2{\sim}20GHz$ frequency considering exposure condition and curing period. The averaged conductivity and dielectric constant in $5{\sim}20GHz$ frequency are reduced to $83{\sim}93%$ and $81{\sim}87%$, respectively with increasing water to cement ratios. Through the linear regression analysis, relationships between EM properties and results from the compressive strength are obtained, which shows higher correlated factor($0.93{\sim}0.94$) in the specimens exposed to room condition. The gradients in dielectric constant for strength results is measured to be higher than those in conductivity by $3.9{\sim}5.1$ times. The results from dielectric constant in room condition shows the most efficient relation for evaluation of strength.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.291-296
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• 2007

We measured potential waveform of load, displacement, micro electric signal generated by rock and mortar fracture using PXI A/D Converter. The rock type used for measurement was used granite, limestone and sandstone, and mortar specimen. we made measuring equipment of physical properties to confirm basic information of physical properties, measured physical properties of rock engineering, electric resistivity and seismic velocity. Potential waveform system was built using PXI A/D Converter and measured potential waveform of load, displacement, micro-electric signal generated using this during uniaxial compressive test by the specimen finished such test of physical properties. Using the saturated rock and mortar specimen, micro electric signal increased, and It didn't increase a signal in dried rock and mortar specimen according as load and strain rate increases. But signal also increased in saturated or dried specimen in case of sandstone. It was possible to check the close correlation relationship the signal and fracture behavior by a compressive load as the signal of fracture position was increased bigger than the other position. It was also possible to check the correlation relationship between physical properties and micro geo-electric signal.