• The KSFM Journal of Fluid Machinery
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• v.19 no.3
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• pp.43-47
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• 2016

Pile foundations constructed on extremely cold regions cause serviceability problems of superstructures from repeated actions of ground freezing and thawing. Oil sand module plants are mainly constructed on seasonal frozen ground. Due to the freezing and thawing actions of grounds, vertical movements of piles have been observed. To solve these erratic pile movement problems, thin vertical layer of PET aggregates is installed around the pile shaft to prevent potential unfavorable pile movements. There is no known method to calculate "thin PET aggregate layer" -surrounded pile shaft resistance (capacity) against vertical loads; therefore, this experimental research is conducted. Specifically, in this study, horizontal (normal) pressures on pile shaft were assessed varying PET aggregate layer thickness based on the experiment.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.75-86
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• 2012

This paper presents some research results on the shrinkage characteristics and frost resistance before and after cracking of FR-ECC(Fire Resistance-Engineered Cementitious Composite). Also, a waterstop performance and exfoliating resistance of multi-layer lining specimens using FR-ECC and flexural performance of beam member by repaired FR-ECC are estimated in this paper. Experimental results indicate that the plastic shrinkage crack and length change ratio of FR-ECC have been reduced as compared with that of the existing repair mortar, and that its crack resistance on the dry shrinkage is improved under the confining stress. As well as FR-ECC has been great in the frost resistance and its tensile properties under the cracked state have been not reduced by freezing and thawing reaction. In addition, beam member by repaired FR-ECC have been increased in the flexural properties such as initial crack moment, yeild moment, and its crack width has been controled in a stable by the frexural failure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.74-81
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• 2013

This research was performed to identify physical properties of polysulfide epoxy polymer concrete for ultra-thin bridge deck pavement, and improve domestic applicability. With the optimum mix ratio determined from mixing experiments of polymer concretes, compressive, flexural, and bond strength were tested to identify its strength properties along with the freezing-thawing resistance test to evaluate its durability in harsh environments. As a result, the tested polymer concretes showed excellent performance in strength and deflection characteristic and all tested strength satisfied the criteria of American Concrete Institute. Moreover, it had better performance under variable temperatures comparing to other existing pavement materials. By the results of freezing-thawing resistance test and strength measurement for specimens underwent the freezing-thawing process, it can be judged that there is no such problem to the concrete's durability. In conclusion, the newly developed polymer concrete in this research has appropriate properties for use in ultra-thin pavement on bridge deck, and moreover it has superior applicability in comparison with former materials due to its improved temperature sensitivity.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.155-158
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• 1995

High durabitiy concrete increasingly sutudied in various countries. This report presents the data on durability related properties such as the chloride ion permeability, the resistance to freezing-thawing, the corrosion of steel and the resistance attack. To promote the actual application of high durability concrete, several series of high durability concrete have been made and applied to actual structures.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.520-527
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• 2020

Hwangtoh is the rich resource that accounts for about 15.0% of the domestic soil, and can be used as the admixture of concrete with Pozzolan characteristics if activated by rapidly freezing after burning with high temperature. In this study, the mortar curbs containing active hwangtoh were produced, based on the mixture for the mortar curbs sold on the market. The substitution rate of active hwangtoh were considered 10.0% and 25.0%, and the test items were selected to compressive and flexural strength tests, freezing/thawing resistance tests, accelerated carbonation tests, and accelerated chloride diffusion tests. In the results of the mechanical performance, it was showed that the highest strength was evaluated in OPC mixture, and the increase in strength was small by the increase of age, which was believed to be due to the fact that most of the strength in each mixture was created in three days of steam curing. The results of the freezing/thawing tests for 28 aged days showed the reduction rate of compressive strength was 85.0% or higher for all specimen, meeting the criteria presented. The accelerated carbonation tests were carried out on the specimen at 28 days of age, and the results showed that the mortar with active hwangtoh had lower carbonation resistance performance than mortar with OPC. The passed charge of each mixture was assessed in accordance with ASTM C 1202 on 28 and 91 aged days. The OPC mixture had "Low" rate and the mortar with active hwangtoh had "Moderate" rate. So it was thought that the mortar with active hwangtoh had appropriate resistance performance for chloride attack.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.22-27
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• 2001

The purpose of this study is development of dry floor tile method that practically used for improving wet method's defect, with resin mat design. PE resin used mat which satisfied with bonding test, waterproof test, resistance to chemical attack test, resistance to impact test and freezing and thawing test is confirmed the basic property.

• Journal of the Korea Institute of Building Construction
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• v.5 no.2 s.16
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• pp.97-105
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• 2005

Concrete structures in the marine environment often deteriorate in the early stage of their service life because of contact with various aggressive conditions. In recent years, the researches on the concrete in the marine environment have been carried out to increase their service life. In this experimental study, the concrete specimens were prepared with various adding contents of inorganic antifouling agent$(0\~3.0wt\%)$ composed of some fluosilicate solution. For evaluation of the properties of concretes containing inorganic antifouling agent, various tests such as setting time, slump loss, compressive strength, water absorption rate, fleering and thawing resistance and SEM of concrete, were conducted. As the results, physical and chemical properties of concretes were improved with an adding of inorganic antifouling agent. From the results of various tests, the optimal adding contents of antifouling agent was $1.0wt\%$.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.34-39
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• 1991

It is well-known that concretes under sea water environment show remarkably degrading phenomena physically by repeatable freeze-thawing action and chemically by penetration of soluted ions in sea water. In this study the influences of type of blending materials, their dosage and W/C ratio on freeze-thawing resistances of hardened cement concrete using foy ash, ground blast furnace slag, silica fume, EVA and SBR under sea-water environment were investigated.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.11-19
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• 2015

The important properties of EVA (ethylene vinyl acetate) redispersible polymer was waterproof, densification of internal pore space of concrete and ball bearing and micro filler. Also, the significant role of polypropylene(PP) fiber was crack control and blockade of movement for deterioration factors. The most studies for EVA were limited in the field of mortar and PP fiber reinforced concrete had been studied in the state of being restricted unit water content, rich mix and mixing much of the fiber without considering construction site. Therefore, the control mix design were applied in ready mixed concrete using 10 % fly ash of total cement weight used in batch plant. On the basis of control mix design, EVA contents ranging from 0 % to 10 % of total cement weight and PP fiber contents ranging from 0 % to 0.5 % of EVA concrete volume were used in the mix designs. The results showed the maximum compressive strength value was measured at EVA 5.0 % and PP fiber 0.1 %, the minimum water absorption ratio was at EVA 10 % and PP fiber 0 %, the durability factor for freezing and thawing resistance was at EVA 5.0 % and PP fiber 0.3 % and the minimum weight reduction ratio of resistance to sulfuric acid attack was at EVA 10 % and PP fiber 0.5 % after curing age 42days. Meanwhile, From these results, PP fiber reinforced EVA concrete would be very benefit, if each optimal mix types were used in hydraulic structures, underground utilities and agricultural structures.

• Journal of the Korean GEO-environmental Society
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• v.15 no.8
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• pp.31-37
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• 2014

In this study, mechanical properties of Very-Rapid Hardening Polymer (VRHP) mortar were investigated. To do it, 75 VRHP mortar specimens were tested by the compressive test, bending test, bonding test, freezing and thawing test, length variation test, and water absorption test. From the test results, it was confirmed that the bond strength of VRHP was higher than that of normal concrete by 50 %, and the resistance of freezing and thawing of VRHP was more excellent than normal concrete. In addition, length variation ratio and water absorption ratio of VRHP were smaller than those of normal concrete by 20 %. Therefore, It should be mentioned that VRHP can be successfully used as the material for repairing the crack of concrete structure.