• Title/Summary/Keyword: Chemical resistance of mortar

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Evaluation of protective coatings for geopolymer mortar under aggressive environment

  • Rathinam, Kumutha;Kanagarajan, Vijai;Banu, Sara
    • Advances in materials Research
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    • v.9 no.3
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    • pp.219-231
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    • 2020
  • The aim of this study is to investigate the durability of fly ash based geopolymer mortar with and without protective coatings in aggressive chemical environments. The source materials for geopolymer are Fly ash and Ground Granulated Blast furnace Slag (GGBS) and they are considered in the combination of 80% & 20% respectively. Two Molarities of NaOH solution were considered such as 8M and 10M. The ratio of binder to sand and Sodium silicate to Sodium hydroxide solution (Na2SiO3/NaOH) are taken as 1:2 and 2 respectively. The alkaline liquid to binder ratio is 0.4. Compressive strength tests were conducted at various ages of the mortar specimens. In order to evaluate the performance of coatings on geopolymer mortar under aggressive chemical environment, the mortar specimens were coated with two different types of coatings such as epoxy and Acrylic. They were then subjected to different chemical environments by immersing them in 10% standard solutions of each ammonium nitrate, sodium chloride and sulphuric acid. Drop in compressive strength as a result of chemical exposure was considered as a measure of chemical attack and the drop in compressive strength was measured after 30 and 60 days of chemical exposure. The compressive strength results following chemical exposure indicated that the specimens containing the acrylic coating proved to be more resistant to chemical attacks. The control specimen without coating showed a much greater degree of deterioration. Therefore, the application of acrylic coating was invariably much more effective in improving the compressive strength as well as the resistance of mortar against chemical attacks. The results also indicated that among all the aggressive attacks, the sulphate environment has the most adverse effect in terms of lowering the strength.

Physical Properties of Polymer Mortar Recycling Waste Concrete Powder as a Filler (폐콘크리트 미분말을 충전재로 재활용한 폴리머 모르타르의 물성)

  • Hwang, Eui-Hwan;Choi, Jae-Jin;Hwang, Taek-Sung
    • Applied Chemistry for Engineering
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    • v.16 no.3
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    • pp.317-322
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    • 2005
  • Nowadays, recycling of aggregates from the waste concrete is in big demand due to the protection of environment and the shortage of aggregates that are needed for ever expanding construction projects. This study was undertaken to examine the feasibility of recycling waste concrete powder produced in the crushing process of demolished concrete as a filler material for polymer mortar. In this study, polymer mortar specimens were prepared by varying the mix proportion of polymer binder (ranging 9~15 wt%), waste concrete powder (ranging 0~20 wt%) substituted for silica powder, 0.1~0.3 mm fine aggregate (ranging 21~24 wt%) and 0.7~1.2 mm fine aggregate (ranging 44~47 wt%). For the prepared polymer mortar specimens, various physical properties such as strength, water absorption, heat water resistance, acid resistance, pore distribution and SEM observation were investigated in this work. As a result, physical properties of polymer mortar were observed to have remarkably improved with an increase of polymer binder, but greatly deteriorated with an increase of substitution quantity of waste concrete powder.

Fundamental Study of Polymer-modified Cement Mortar for Maintenance in Concrete Structure According to Ambient Temperature (온도에 따른 콘크리트 구조체 단면 보수용 폴리머 모르타르의 기초적 연구)

  • Seo, Jung-Pil;Kim, Jae-Won;Lee, Jung-Koo;Choi, Hun-Gug;Kang, Cheol;Kim, Jin-Man
    • 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.

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Sulfuric Acid Resistance Evaluation of Repair Mortar Substituted Blast Furnace (고로슬래그를 치환한 보수 모르타르의 내 황산성 평가)

  • Kim, Wan-Su;Jang, Jong-Min;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.25-26
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    • 2019
  • The Reinforced concrete structure is deteriorated in durability due to various deterioration factors such as acid, salt, etc., and thus requires repair and reinforcement. In this study, compressive strength and weight change were measured by substituting blast furnace slag with excellent chemical resistance. As a result, the decrease in compressive strength decreased in proportion to the blast furnace slag substitution rate, and in the case of BFS40, the strength increased after sulfuric acid immersion. The weight change also decreased in proportion to the replacement amount.

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Classification of Alkali Activated GGBS Mortar According to the Most Suitable Usage at the Construction Site

  • Thamara, Tofeti Lima;Ann, Ki Yong
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.1
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    • pp.56-63
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    • 2020
  • The usage of OPC-free alkali activated ground granulated blast furnace slag(GGBS) mortar has been widely studied on the previous years, due to its advantages on sustainability, durability and workability. This paper brings a new view, aiming to classify the best application in situ for each mortar, according to the type and activator content. By this practical implication, more efficiency is achieved on the construction site and consequently less waste of materials. In order to compare the different activators, the following experiments were performed: analysis of compressive strength at 28 days, setting time measured by needles penetration resistance, analysis of total pore volume performed by MIP and permeability assessment by RCPT test. In general, activated GGBS had acceptable performance in all cases compared to OPC, and remarkable improved durability. Following the experimental results, it was confirmed that each activator and different concentrations impose distinct outcome performance to the mortar which allows the classification. It was observed that the activator Ca(OH)2 is the most versatile among the others, even though it has limited compressive strength, being suitable for laying mortar, coating/plaster, adhesive and grouting mortar. Samples activated with NaOH, in turn, presented in general the most similar results compared to OPC.

Hot Water Resistance of Polymer Mortar Composites Depending on Unsaturated Polyester Resin Types (불포화폴리에스테르 수지의 형태에 따른 폴리머 모르타르 복합재료의 내열수성)

  • Hwang, Eui-Hwan;Song, Min-Kyu;Kim, Yong-Yeon
    • Applied Chemistry for Engineering
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    • v.29 no.2
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    • pp.201-208
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    • 2018
  • The ortho- and iso- type unsaturated polyester resins were synthesized and used as a polymer binder of the polymer mortar composite. Styrene monomer and acrylonitrile were used as a diluent for the unsaturated polyester resin. Methyl ethyl ketone peroxide (MEKPO) and cobalt octoate (CoOc) were used as a curing agent and an accelerator, respectively. Four kinds of unsaturated polyester resins were prepared according to types of the resin and diluent, and used as a polymer binder in the preparation of the specimen. A total of 16 polymer mortar specimens were prepared according to the added amount of the polymer binder and subjected to a hot water resistance test, followed by compressive and flexural strength tests, and pore and SEM analyses. As a result, it was found that the strength of the specimen using the iso-type unsaturated polyester resin as the polymer binder was better than that of using the ortho-type unsaturated polyester resin. The total pore volume and diameter measured after the hot water resistance test were reduced compared to the values before the test. In the micrographs observed before the hot water resistance test, the polymer binder, filler and fine aggregate were firmly combined to the co-matrix, but the polymer binder was mostly decomposed in the micrographs observed after the test.

Flexural Reinforcement of RC Structures with composite fiber rods inserted in high strength special purposed polymer mortar for various deteriorated conditions. (박막형 고강도 폴리머 및 열화원인별 적용 몰탈내에 섬유로드를 삽입하는 RC 구조물의 보강공법 연구)

  • 정원용;이상근;박홍진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.828-835
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    • 2000
  • In recent years, RC structures need reinforcement due to physical and chemical deterioration, reduction of serviceability and structural capacity. For reinforcement of RC structures, steel plate attachment, area increase and composite fiber sheet attachment methods are used, but there are some problems like weight increase, workability, quality control and fire resistance capacity. This study presents the effectiveness of flexural reinforcement of RC beams using composite rods that are inserted in high strength special purposed polymer mortar.

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Burn-up Characteristics of Polymer-Modified Cement Mortar Used for Building Repair (고온시에서의 폴리머 시멘트 모르타르의 연소특성에 관한 연구)

  • Kim, Hyung-Jun;Noguchi, Takahumi
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2012.05a
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    • pp.295-298
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    • 2012
  • Repair and strengthening is necessary to extend the service life of existing buildings. Polymer-modified cement mortar (PCM) has been extensively used as a high performance material particularly for finishing and repairing works in concrete building because of itsexcellent adhesion, waterproofing, resistance to chemical attack, and workability. As PCM contains organic polymer, it is necessary to clarify its properties at high temperature under fire, on which sufficient data are not available. This paper evaluated the burn-up characteristics of polymer-modified cement mortar with cone calorimeter test, non-combustibility test and flammability test with experimental parameters such as the types of polymer, unit-polymer content, polymer-cement ratio and thickness of the specimen.

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A study on the mechanical properties of the polymer cement mortar in a high temperature region (고온영역에서의 폴리머시멘트모르타르의 역학적 특성연구)

  • Yoon, Ung-Gi;Seo, Dong-Goo;Kwon, Young-Jin;Kim, Hyung-Jun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.11a
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    • pp.113-114
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    • 2014
  • Though polymer cement mortar is widely used to repair or reinforce concrete as it has superior adhesion, dense internal structure, chemical resistance, and workability in comparison to those of general cement mortar, studies on its behaviors in high temperature environment such as fire is urgently required. Accordingly, in this experiment, the degrees of reduction in the compressive strength at different temperatures was grasped applying ISO834 Heating Curve, and the effect of polymer content and type on compressive strength could be determined. As a result of this experiment, it is found that polymer type and content have a big effect on reduction of compressive strength in high temperature range, and not only the dynamic characteristics but also the combustion characteristics in high temperature range are required to be studied considering occurrence of a fire in the future.

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Influence of Admixtures on Strengths and Freezing and Thawing Resistance of Cement Mortar for Precast Products (혼화재료가 공장제품용 시멘트 모르타르의 강도 및 동결융해 저항성에 미치는 영향)

  • 한천구;신병철;김기철;이상태
    • Journal of the Korea Concrete Institute
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    • v.12 no.3
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    • pp.11-19
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    • 2000
  • It has been reported that few manufacturers of cement mortar for precast products use chemical and mineral admixture due to the absense of restrictions related to the application of admixture and the poor manufacturing facilities. Therefore, this paper is intended to contribute to the improvement of quality by investigating the properties of cement mortar for precast products using fly ash, blast furnace slag and AE water reducing agent. According to the test results. it was found that the cement mortar products using fly ash and AE water-reducing agent had better qualities than those of ordinary portland cement.