• Journal of the Korea Institute of Building Construction
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• v.14 no.1
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• pp.37-44
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• 2014

Recently, many efforts related to the utilization of industrial by-products have been made to reduce carbon dioxide emissions in the construction industry. Of these various efforts, concrete incorporating ground granulated blast furnace slag (BFS) provides many advantages compared to conventional concrete, such as high long-term compressive strength, improved durability and economic benefits because of its latent hydraulic property, and low compressive strength at early curing age. This paper investigates the compressive strength of high-activated ground granulated blast furnace slag blended mortar with slag by-product S type(SBP-S). The results of the experiment revealed that incorporating high-activated ground granulated blast furnace slag would affect the compressive strength of mortar. It was found that increasing the Blaine fineness and replacement ratio of slag by-product S type shows high compressive strength of mortar at early curing age because of its high $SiO_2$ and CaO contents in the slag. It is confirmed that an increase of curing age does not affect the compressive strength of mortar made with slag by-product S type at a high curing temperature. Moreover, it is possible to develop and design concrete manufactured with high-activated ground granulated blast furnace slag as binder considering the acceleration curing conditions and mix proportions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2008.05a
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• pp.93-97
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• 2008

The study analyzed on each kind of basic characteristics in mortar to prove an effect of pre-mix cement, ultra high strength binder. The results were as follows. in characteristics of not set mortar, fluidity time was the quickest at the time of using POBSA and was more delayed at the time of using Fly Ash than at the time of using Blast Furnace Slag as a binder. Mortar ring flow and flow con flow got smaller as fluidity time got longer, on the contrary to fluidity time. Unit capacity mass was smaller at the time of using Fly Ash than at the time of using Blast Furnace Slag. According to pre-mix, it was difficult to discover a regular tendency. In characteristics of hardening mortar, the 28th day compressive strength was better than thing mixed after measuring separately in pre-mix. According to a binder's kind, Silica Fume B, C was better than Silica Fume A.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.371-376
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• 2001

The purpose of this study is to investigate toughening of unsaturated polyester resin by addition of polyuretane liquid rubber. In general, unsaturated polyester resin has strong brittleness in spite of its high strength Therefore; it is difficult to use unsaturated polyester mortar for the place where impact resistance is demanded. In this study, it was evaluated strength and Gf by using to polyurethane liquid rubber. As a result, the toughness of unsaturated polyester mortar was increased by polyuretane liquid rubber.

• Journal of the Korea Institute of Building Construction
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• v.12 no.5
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• pp.460-467
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• 2012

When recycled aggregate with old mortar and particles is used in concrete mixing, such aggregates can affect hydration reaction by promoting or inhibiting it. In this study, the possibility of hydration reaction on old mortar and particle was analyzed. Hydration reaction was carried out in old mortar that is finely crushed by an impact machine in the production of recycled aggregates, and it was found that this did have an impact on the strength development of concrete. Unlike in old cement, the hydration reaction did not progress in the particles, and it had high amounts of silica powder and calcium carbonate. In conclusion, the old mortar can have the influence of improving compressive strength, but the particles can delay the setting time of recycled aggregate concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.04a
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• pp.59-62
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• 2007

Nowadays, polymer-cement mortars are widely used in construction field(floorings and pavements, water-proofings, adhesives, repair materials, deck coverings, anti-corrosive linings) Because of excellent performance such as high tensile and flexural strength, waterproofness, excellent adhesion, good durability, improved wear and chemical resistances. This article presents the results of experimental study that investigates the effect of ambient temperature on the strength properties of polymer-modified cement mortar. Results show that when increasing the polymer proportion in mortar on different ambient temperature, the compressive strength and flexural strength are decreased, and also alkali resistance is decreased.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.179-180
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• 2020

CO2 emissions are caused by cement manufacturing process. To solve this problem construction industry are using industrial by-products to replace cement. In this study, three different industrial by products were used and mixed with hybrid fibers to enhance bond strength. As the result, Regardless of the mixing rate of silica fume, the compressive strength of the ternary non cent mortar was higher than that of OPC and binary. And mixed hybrid fibers cured by room temperature compressive strength were 23% higher than those without hybrid fibers.

• Computers and Concrete
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• v.8 no.5
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• pp.491-510
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• 2011

Before deciding if structures exposed to high temperature are to be repaired or demolished, their final state should be carefully examined. Destructive and non-destructive testing methods are generally applied for this purpose. Compressive strength and color change in mortars are observed as a result of the effects of high temperature. In this study, ordinary and pozzolan-added mortar samples were produced using different aggregates, and exposed to 100, 200, 300, 600, 900 and $1200^{\circ}C$. The samples were divided into two groups and cooled to room temperature in water and air separately. Compression tests were carried out on these samples, and the color change was evaluated by the Munsell Color System. The relationships between the change in compressive strength and color of mortars were determined by using a multi-layered feed-forward Neural Network model trained with the back-propagation algorithm. The results showed that providing accurate estimates of compressive strength by using the color components and ultrasonic pulse velocity design parameters were possible using the approach adopted in this study.

• International Journal of Concrete Structures and Materials
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• v.10 no.1
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• pp.113-124
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• 2016

This paper presents the effect of silica fume and nano silica, used individually and in combination with the set accelerator and/or hydrated lime, on the properties of class F high volume ultra fine fly ash (HV-UFFA) cement composites, replacing 80 % of cement (OPC). Compressive strength test along with thermogravimetric analysis, X-ray diffraction and scanning electron microscopy were undertaken to study the effect of various elements on the physico-chemical behaviour of the blended composites. The results show that silica fume when used in combination with the set accelerator and hydrated lime in HV-UFFA cement mortar, improves its 7 and 28 day strength by 273 and 413 %, respectively, compared to the binary blended cement fly ash mortar. On the contrary, when nano silica is used in combination with set accelerator and hydrated lime in HV-UFFA cement mortar, the disjoining pressure in conjunction with the self-desiccation effect induces high early age micro cracking, resulting in hindering the development of compressive strength. However, when nano silica is used without the additives, it improves the 7 and 28 day strengths of HV-UFFA cement mortar by 918 and 567 %, respectively and the compressive strengths are comparable to that of OPC.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4C
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• pp.283-290
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• 2006

Concrete has advantages in fire situations as it is non-combustible and has low thermal conductivity. However, concrete that is not designed against fire can experience significant explosive spalling from the build-up of pore pressures and internal tensile stresses when heated. In this study, the performance of wet-mixed high strength sprayed polymer mortar for fire resistance of tunnel system was evaluated by experimentally and numerically. The fire test was performed in fire resistance(electric) furnace according to RABT(Richtlinien fur die Ausstatung und den Betrieb von $Stra{\beta}entunneln$) time heating temperature curve, so as to evaluate the temperature distribution with cover thickness of wet-mixed high strength sprayed polymer mortar for fire resistance of tunnel system. Based on experimental results and numerical analysis, the proper cover thickness of wet-mixed high strength sprayed polymer mortar determined the more than 4cm.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.309-312
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• 2004

The hydraulic structure of the hydroelectric power plant such as aqueduct tunnels and the drainage canal became old. Therefore, because the concrete surface of the aqueduct tunnel has received severe damage by wear-out and the crack etc the repair is demanded. This research examined the applicability of the repair mortar which mixed the fly ash and an artificial aggregate by using the very high early strength cement. As a result, good Quality repair mortar which satisfied the demand performance more than self-flow 270mm and compressive strength $50N/mm^2$ (age of 28days) adjusting of water cement ratio by using the MTX cement be able to be manufactured.