• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.29-30
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• 2013

폴리머 시멘트 모르타르(Polymer-Modified Cement Mortar, 이하, PCM으로 칭함)는 일반 시멘트 모르타르와 비교해서 접착성, 치밀성, 내약품성, 시공성등이 우수한 재료로, 콘크리트 구조물의 보수 보강에 필수불가결한 재료로 인식되고 있다. 그러나, 혼입된 폴리머는 유기물 재료로, 화재와 같은 고온을 받는 경우에는 무기계 재료인 일반 모르타르 및 콘크리트와는 또 다른 고온역에서의 성상을 보일 것으로 예상된다. 이로 인해, PCM으로 보수 보강된 건축물에 화재가 발생할 경우, 고온에서의 안전성 및 화재 후의 보수 보강 필요성에 대한 평가를 행할 필요가 있다. 이에 본 논문에서는 평가시 기본적인 데이터로 활용될 수 있는 PCM의 고온노출시의 역학적 특성에 대한 검토방안으로, 기존의 실험조건 및 실험방법을 응용한 새로운 실험방법을 적용, 비교검토를 행하고, 고온영역에서의 PCM의 역학적 특성에 대해 고찰했다.

• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.157-165
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• 1996

The purpose of this study is to develop the epoxy-modified mortars and concretes without hardener having a good balance between performance and cost. In this study, the epoxy-modified and concretes without and with the hardener are prepared with various polymer-cement ratios, and tested for the mechanical properties of the epoxy-modified mortars and concretes without and with the hardener. From the test results, the epoxy-modified mortars and concretes without the hardener having an excellent mechanical properties are developed at low polymer-cement ratios of 10 to 20% compared with those of conventional epoxy-modified mortars and concretes with the hardener.

• 레미콘
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• no.9 s.25
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• pp.93-98
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• 1990

• Resources Recycling
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• v.21 no.1
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• pp.30-40
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• 2012

Electric arc furnace slag is made in ironworks during steel refining, it is been increasing chemical and physical resistibility using ageing method of unstable state of melting steel slag for using concrete's fine aggregates. Which is been changing stable molecular structure of aggregates, it restrains moving of ion and molecule. In Korea, KS F 4571 has been prepared for using the electric arc furnace oxidizing slag to concrete aggregates(EFS). In this study, Electric arc furnace oxidizing slag is used in the PRCC(Polymer Rapid setting Cement Concrete) which is applied a bridge pavement of rehabilitation, largely. The results showed that the increment of compressive strength development by 10- 20%. The flexural strength of EFS-Con increased greatly as the electric arc furnace oxidizing slag changed. The compressive strength and flexural strength developed enough for opening the overlayed EFS-Con to the traffic after 4 hours of EFS-Con placement. The permeability of EFS-Con was evaluated as negligible due to its very low charge passed. Thus, EFS-Con could be used at repairing or overlaying the concrete at fast-track job sites.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.218-225
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• 1997

This study was performed to evaluate the physical and mechanical properties of surlightweight polymer concrete using synthetic lightweight aggregate. The following conclusions were drawn; 1. Unit weight was in the range of $810~970kgf/m^3$, the unit weights of those concrete were decreased 58~65% than that of the normal cement concrete. 2. The highest strength was achieved by $P_1$, it was increased 112% by compressive strength, 378% by bending strength and 290% by tensile strength than that of the normal cement concrete, respectively. 3. Ultrasonic pulse velocity was in the range of 2,206~2,595m/s, which was low showed compared to that of the normal cement concrete. 4. Durability of surlightweight polymer concrete was superior to that of the normal cement concrete. 5. Compressive, tensile and bending strength were largely showed with the increase of unit weight. But, ultrasonic pulse velocity was low showed with the increase of unit weight.

• Applied Chemistry for Engineering
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• v.20 no.1
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• pp.67-74
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• 2009

Nowadays, recycling of recycled aggregates from the waste concrete is seriously demanded for the protection of environment and the shortage of aggregates owing to the large scale construction project. In this study, for the development of polymer composite recycling recycled aggregates from the waste concrete, twenty five specimens of the polymer composite were prepared with the five levels of replacement ratios of recycled aggregates (0, 25, 50, 75, 100%) and polymer-cement ratios (0,5, 10, 15, 20%), respectively. For the evaluation of the performance of polymer composite specimens, various physical properties such as compressive and flexural strengths, water absorption, hot water resistance, total pore volume and porosity were investigated. As a result, physical properties of polymer composite were remarkably improved with an increase of polymer cement ratios, but greatly decreased with the replacement ratios of recycled aggregates.

• Journal of the Korea Institute of Building Construction
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• v.23 no.2
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• pp.133-142
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• 2023

In this study, the fire resistance capabilities of polypropylene fiber-reinforced polymer-modified cement mortar were assessed to guarantee the fire resistance fo this materials, commonly employed in the repair of concrete structures. Experimental outcomes revealed that an increased water and polymer content heightened the likelihood of spalling, while longer polypropylene fibers and elevated polymer concentrations proved more effective in mitigating spalling.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.119-126
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• 2012

Portland cement production-1.5billion tonnes yearly worldwide-contributes substantially to global atmospheric pollution(7% of total of $CO_2$ emissions). Attempts to increase the utilization of fly ash, by-products from thermal power plant to partially replace the cement in concrete are gathering momentum. But most of fly ash is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the sources of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effect reduction of $CO_2$ gas. In this study, we investigated the influence of the compressive strength of mortar on alkaline activator and curing condition in oder to develop cementless fly ash based alkali-activated concrete. In view of the results, we found out that it was possible for us to make alkali-activated mortar with 70MPa at the age of 28days by using alkaline activator manufactured as 1:1 the mass ratio of 9M NaOH and sodium silicate and applying the atmospheric curing after high temperature at $60^{\circ}C$ for 48hours.

• Journal of the Korea Concrete Institute
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• v.27 no.6
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• pp.633-640
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• 2015

Polymer cement slurry (PCS) is made from organic polymer dispersion and cement has good adhesion to steel, waterproofness and acid resistance due to being of polymer films formed in cement slurry. The purpose of this study is to evaluate the bond strength of coated rebar by polymer cement slurry made of EVA and ultra high-early strength cement. The test pieces are prepared with EVA polymer dispersion and ultra high-early strength cement having four types of polymer-cement ratios, four types of coating thicknesses and four curing ages, and tested for the bond strength test. From the test results, in general, bond strength of PCS-coated rebar is better than that of uncoated rebar and epoxy-coated rebar. It is also high bond strength at curing ages of 7-day, and coating thicknesses of $75{\mu}m$ and $100{\mu}m$. The maximum bond strength of PCS-coated rebar with ultra high-early strength cement and EVA at polymer-cement ratio of 80%, and coating thickness of $100{\mu}m$ is about 1.32 and 1.38 times respectively, the strength of uncoated rebar and epoxy-coated rebar. It is apparent that the curing age, coating thickness, type of polymer and cement are very important factors to improve the bond strength of PCS-coated rebar to cement concrete. We can have basic information that PCS-coated rebar with polymer-cement ratio of 80% or 100% and coating thickness of $100{\mu}m$ at curing age of 1-day can replace epoxy-coated rebar.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.73-80
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• 2013

Polymer cement slurry (PCS) made from organic polymer dispersion and cement has good adhesion to steel, waterproofness and acid resistance due to being of polymer films formed in cement slurry. The purpose of this study is to evaluate the mix design conditions at early curing age of PCS-coating material effected on improvement in bond strength of coated rebar. The test pieces are prepared with two types of polymer dispersions such as St/BA and EVA, four polymer-cement ratios, two types of cement, four coating thicknesses and three curing ages, and tested for the bond strength test. From the test results, in general, bond strength of PCS-coated rebar is better than that of uncoated rebar and epoxy-coated rebar. It is also high bond strength at curing ages of 7-day or less, and coating thicknesses of $75{\mu}m$ and $100{\mu}m$. The maximum bond strength of PCS-coated rebar at curing age of 3-hour is almost same as that of curing age of 1-day and 7-day. The maximum bond strength of PCS-coated rebar with ultra high-early strength cement and St/BA at polymer-cement ratio of 80%, and coating thickness of $100{\mu}m$ is about 1.52 and 1.58 times respectively, the strength of uncoated rebar and epoxy-coated rebar. It is apparent that the curing age, coating thickness, type of polymer and cement are very important factors to improve the bond strength of PCS-coated rebar to cement concrete. We can have basic information that PCS-coated rebar with curing age at 3-hour and coating thickness of $100{\mu}m$ can replace epoxy-coated rebar.