• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.213-214
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• 2011

This study investigates the fundamental properties of bast furnace-based mortar made with recycled fine aggregate. Results showed that increasing recycled fine aggregate accelerated setting time, proportionally increased the compressive and flexural strength of mortar specimens. However, it is concluded that for quality and cost effectiveness, the optimum content of this recycled fine aggregate in mortar was found to be 80%.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.215-216
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• 2011

This study investigates the effect of partial replacement with cement on the properties of blast furnace slag-based mortar. Recycled fine aggregate with various contents was used to activate the hydration of blast furnace slag in the mortar and compared its effect on strength development. Results showed that increasing cement and recycled fine aggregate increased the strength of mortar specimens. However, this study found that the mortar made with partial replacement of river sand with recycled fine aggregate of 20% developed a similar strength to the strength that cement with 10% can achieved.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.576-582
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• 2000

Two type of expanding cement generally referred to as CSA with Hauyne(3CaO 3Al2O3 CaSO4) and Quick lime(CaO). Hauyne is formed to ettringite when there are presented with CaO and CaSO4, and CaO reacts wtih water to form Ca(OH)2. REcently, the mechanism of compensation and expand mortar or concrete tend to same and it has been used improving on its shrink property. The volume of cement paste varies with its water content shrink with drying and re-wetting. Concrete and mortar works are required shrinking compensation and expansion properties to reduce of potential crack. The use of expansion cement may improve on its shrinking volume changes. CSA dosages for shrinking compensation limited by cement weight, but obtained difference expansion rate with varied W/C or inorganic admixture. This paper studies expansion rate according to expansion cement dosages, water and inorganic admixtures as Silica fume. Therefor, the expansion factor has to considered before the application.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.833-840
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• 1990

For the development of multi-functional materials which has water reducing power, air entraining power and waterproofing power as well as blending additive in cement mortar the coal ash was modified with asphalt-stearic acid or asphalt-boiled oil mixtures by mechanical treatment. And the physical properties of cement mortar blended with modified coal ashes were compared with those of the water-tightness-cement mortar and the ordinary-portland-cement mortar added with AE.water reducing agent. The mortar of coalash-blend-cement modified with asphalt-stearic mixture was increased acid about 20% in initial strengths and decreased about 20% in water absorption ratio than those of ordinary coalash-blend-cement. The mortar of coalash-blend-cement modified with asphalt-bolied oil mixture was similar to the cement mortar added with AE.water reducing agent in water reduction ratio, air entraining conents and the initial strengths, also was similar to the water-tightness-cement mortar in water absorption and water permeability ratios.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.137-140
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• 1998

An entrained air is important in improving freeze/thaw resistance to the concrete structures. To achieve a proper degree of air entrainment, air entraining admixtures(AEA) are typically added to the concrete mixture, but it has been noted that an increase in the carbon content(LOI) of fly ash causes problems in proper air entrainment in concrete. In this study, the entrained air content of mortar with fly ash as an additive was considered according to the mix design as a type of AEA, adding amount of fly ash and AEA, and the elapsed time. Moreover, two different types of measurement were also tired for air content.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.231-236
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• 1998

In general, the drying shrinkage of polymer-modified mortars using redispersible polymer powders is much higher than that of unmodified mortar. The purpose of this study is to reduce the drying shringkage of polymer-modified mortars using a redispersible poly(ethylene-vinyl acetate) (EVA) powder, which is widely used for the manufacture of prepackaged-type polymer-modified mortar products at present. Polymer-modified mortars using the redispersible EVA powder with powdered shrinkage-reducing agent were prepared with various polymer-cement ratios and shrinkage-reducing agent contents, and tested for drying shrinkage and strength. From the test results, the drying shrinkage of the redispersible EVA powder-modified mortars with a powdered shrinkage agent is remarkably reduced with increasing shrinkage-reducing agent content, and becomes approximately a half of that of the redispersible EVA powder-modified mortars with the same polymer-cement ratios and without the shrinkage-reducing agent at a shrinkage-reducing agent content of 6%.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.237-242
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• 1998

Covering mortar as a filter for permeable polymer concrete is necessary for good permeability from filtration continuously. Therefore, this paper is intended as an evaluation of the mechanical properties and permeability of permeable polymer concrete covered with polymer mortar as a filter. An optimum permeable polymer concrete is selected in various mix proportions, and three different polymer mortars were cast immediately following on the casting of the base permeable polymer concrete. And they are tested for compressive and flexural strengths, adhesion in tension, hardening shrinkage and permeability . From the test results, binder and filler contents in mix proportions had a great influence on the permeability of polymer concretes. The mechanical properties of permeable polymer concretes covered with polymer mortars using crushed stone are superior to other filters, and hardening shrinkage is the smallest in filters. It is apparent that adhesion between the base permeable polymer concrete and polymer mortar is affected by the degree of hardening shrinkage. From this study, proper mix proportions can be recommended in the consideration of properties of the permeable polymer concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.255-260
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• 1998

As a part of the study on the development of augered pile method, this study is intended to investigate the properties of fresh and hardened mortar with the proportion of expansion additives. With the increase of proportion of expansion additives, the fluidity of mortar shows a decrease while air content increases and setting time gets retarded. It show the satisfactory property in strength at 5% of proportion, and shows more expansion with the increase of proportion of expansion additives and sand/cement ratio. In conclusion, both of strength and expansion reveal appropriate at 10% of proportion of expansion additives.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.103-107
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• 1995

The intention of this study is to reduce the drying shrinkage of the cement mortar using the shrinkage reducing agent and the inorganic admixture. In this experiment the drying shrinkage strain, rate of weight loss and strength have been measured depending on age using the motar specimen. The result show that the usage of shrinkage reducing agent up to 1.5% will give an effect of approximately 30% without loss of strength, and the efficiency will increase together with the inorganic admixture. Also, as the amount of shrinkage reducing agent increases, the rate of weight loss increases. Drying shrinkage reduces at the same rate of weight loss.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.145-149
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• 1995

This study is to recognize the effect of silica-fume, fly-ash, and chemical proportion in mortar that have salt on the inside affect steel bar corrosion. water-binder ratio, 0.5, compounds, each of 10, 15, 20% by weight of cement, Nacl mixing weight, 0.5, 1.0, 2.0% by weight of binder, The speciment is sealed and cured for 28days, the corrosion area ratio and weight reduction ratio is measured after the accelerated corrosion test of 20 cycles. The conclusion shows that there is no suppression effect of steel bar corrosion of silica-fume, fly-ash, in case of having salt on the inside.