• Journal of Ocean Engineering and Technology
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• v.10 no.4
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• pp.103-108
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• 1996

To syudy the change of prtential in the mortar-embedded precorroded rebar, a half cell method was adapted. The rebar was corroded by the salt spray and then the rebar embedded in the mortar. A saturated copper sulfate feference electrode was used. The corrosion potential of the rebar in the mortar specimen cured in air was increased, whereas that of the rebar cured in water was decreased with aging. The corrosion potential of the rebar in the mortar was decreased with corroded time by the salt spray. As the mortar thickness covered the rebar was increased, the corrosion potential of the rebar in the mortar was increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1541-1548
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• 2015

In this study, strengthening methods of floor surface finishing mortar are investigated to prevent the cracks using crack inhibitor agents, water reducer agent and resin. As a results, The number of crack and compressive strength of the specimen containing water reducer agent or resin had more effective than other specimens containing inhibitor agents at 7 days. And the highest compressive strength specimen showed the relatively no crack, but the lowest compressive strength specimen showed a lot of crack. Therefore the relationship between the crack growth and the compressive strength had proportional connection. A base on the mock-up test, long-term monitoring of the on-site applied to mixing design type3 showed the few cracks.

• Advances in concrete construction
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• v.2 no.4
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• pp.249-259
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• 2014

Mortar is a masonry product which is matrix of concrete. It consists of binder and fine aggregate and moreover, it is an essential associate in any reinforced structural construction. The strength of mortar is a special concern to the engineer because mortar is responsible to give protection in the outer part of the structure as well as at a brick joint in masonry wall system. The purpose of this research is to investigate the compressive strength and tensile strength of mortar, which are important mechanical properties, by replacing the cement and sand by stone dust. Moreover, to minimize the increasing demand of cement and sand, checking of appropriateness of stone dust as a construction material is necessary to ensure both solid waste minimization and recovery by exchanging stone dust with cement and sand. Stone dust passing by No. 200 sieve, is used as cement replacing material and retained by No. 100 sieve is used for sand replacement. Sand was replaced by stone dust of 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% by weight of sand while cement was replaced by stone dust of 3%, 5%, and 7% by weight of cement. Test result indicates that, compressive strength of specimen mix with 35% of sand replacing stone dust and 3% of cement replacing stone dust increases 21.33% and 22.76% respectively than the normal mortar specimen at 7 and 28 days while for tensile it increases up to 13.47%. At the end, optimum dose was selected and crack analysis as well as discussion also included.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.17-22
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• 2002

Chloride ions have a tendency to penetrate into concrete and proceed the corrosion by depassivating rebar surface. Thus the deteriorated concrete is subject to experience severe degrading of durability under marine environment. Physical properties of mortar, such as, compressive strength and penetration depth of chloride ion were investigated. And to investigate the effect of containing SG, FA in mortar, the diffusion coefficient of chloride was measured through an electro - migration test. The diffusion coefficient of chloride was decreased with the increase of replacement ratio of SG compared with plain specimen.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.73-78
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• 1993

This study was performed for the purposes of estimating steel corrosion of concrete structures under the environment of seawater. The corrosion of steel was accelerated in artificial seawater with seven kinds of specimen which was embedded in mortar. By measuring choride content in mortar, half cell potential and corrosion area ratio, the degree of steel corrosion can be assumed.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.563-566
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• 2000

The study is to examine the drying shrinkage reducing method of mortar using organic shrinkage reducing agent. According to the experiment result, when 2% and 4% of organic shrinkage reducing agent were added, 40% and 50% of the shrinkage rate of mortar were obtained. Also, in the cracking test of plate-shape specimen, the usage of shrinkage agent 2% reduced about 60% of the total cracking length compare to total cracking length the usage of portland cement, the usage of shrinkage agent 4% was not happened crack until 90 days. Accordingly, the usage of shrinkage agent show good effect in prevention of crack.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.67-68
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• 2023

After mixing the pozzolan-based powder and water repellent with porosity into the cement mortar, microanalysis and measurement of the water repellent contact angle confirmed that the NZS specimen using natural zeolite had the highest contact angle. The specific surface area is increased due to the porosity of natural zeolite, so the adhesion of silane-siloxane is relatively better than that of FA, and it is judged to have a uniform distribution inside the mortar.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.828-833
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• 2003

In this paper, a study on fracture characteristics of chemically prestressed mortar with addition of expansive additives was carried out. Uni-axial tension tests with reinforced mortar specimen restrained by embedded reinforcing bar and three point bending tests with notched steel fiber reinforced beams were carried out to verify the characteristics of the cracking behavior, the tension stiffening effect due to bond between rebar and mortar, and fracture characteristic. Tension stiffening curve for the chemically prestressed mortar was obtained from uni-axial tension test. And increased fracture energy due to the chemical prestress was also obtained from bending test and tension softening curve for chemically prestressed mortar was also obtained.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.108-109
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• 2018

Cement is the most widely used but generates a lot of CO₂, so we need a material to replace it. Using industrial by-products such as Silica Fume(SF), Blast furnace Slag(BS) and Fly Ash(FA) bring some advantages including CO₂ reduction and resource recycling. However, there is a limit to improve performance when using only one material. Therefore, the synergy effects of No cement binary mortar and ternary mortar were analyzed and compared. As a result, No cement ternary mortar had the strength higher than binary mortar. among ternary mortars, the specimen mixed 50% of BS had the highest strength. However, when SF was mixed by 20%, the flowability reduces. so 10% of SF, 40% of FA and 50% of BS is considered as the optimal mixing ratio.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.2
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• pp.109-116
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• 2007

The purpose of this paper is to evaluate the fire resistant performances of load-bearing wall using both composite and steel stud panel infilled with light-weight formed mortar under axial loading according to KS F 2257(1999). The minimum requirement of 2 hours fire resistant rating is needed for the residential and commercial buildings under the fire regulation of Korea. From test results, it is found that two types of specimen composed of the hybrid stud and steel stud panel filled with light-weight formed mortar fited in with the requirement of 2 hours fire resisting rate for the load-bearing wall. In the conclusions, the specimen with hybrid stud shows predominating fire-resistant performance on the adiabatic effects rather than that of the steel stud specimen.