• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.456-461
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• 1997

The purpose of this experimental study are to produce a durable concrete and to investigate the various factors that can deteriorate the concrete when freezing and thawing activity. Among the various factors that can influence the frost resistance of concrete, this study examined mainly the relationship of the frost resistance with the water-cement ratio, admixture and admixture replacement ratio and propose the available water-cement ratio, admixture and admixture replacement ratio.

• Journal of the Korean Society of Safety
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• v.31 no.4
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• pp.82-89
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• 2016

In this paper, various of experiments were performed for checking the usefulness of Pozzolan Inorganic Polymer(PIP) Waterproof Admixture. The results of the experiment enabled to set the optimum mixture ratio of PIP waterproof admixture as 3.5%. Then, the test specimen mixed with PIP waterproof admixture was produced and consider whether meeting the quality standard of waterproofing admixture for concrete (KS F 4926) From the results, all the items such as mechanical properties and durability were meet the quality standard of KS. The PIP waterproof admixture concrete shows the high resistance of absorption, permeability and chloride ion penetration thanks to its internal components such as siliceous powder, zinc stearate and dispersive polymer.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.83-88
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• 1999

The purpose of this study is to offer the basic information of waterproofing admixture of powder for field application. Through before study and fly ash in mortar, Various properties as fly ash ratio in concrete were checked. According to the experimental result, it was shown that proper Waterproofing admixture of powder increased by cement weight in concrete was generally positive effect to flowing, compressive strength, suction ratio of water, length change ratio. So if Waterproofing admixture of powder is well done quality considered as good on application of concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.787-792
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• 2003

The purpose of this study is to suggest the fundamental data of durability which effects on the Carbonation of concrete by adding various admixture additives. Thus, We have experimented the accelerated test on the concrete blending which was admixed by blast furnace slag, fly-ash, silica fume , durability amelioration and it was cured 7weeks after twenty eight days water curing. The result of this experiment is that Carbonation speed increased extremely when water cement ratio went up, and by growing of replace cement ratio of admixture additives. The specimen which was added fly-ash, blast furnace slag, silica fume has the faster Carbonation speed than the specimen which was not added admixture additives. All of these specimen, fly-ash has the fastest progress speed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.11a
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• pp.103-106
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• 2006

This study investigates spalling properties of 60MPa class, high performance concrete, made with the various influential parameters, such as, blaine of cement, mineral admixture and polypropylene(PP) fiber contents. Totally 21 parameters of ${\phi}100{\times}200mm$ in size was fabricated; three specimens for variance in blaine of cement, 4 specimens for combination of mineral admixture type, along with 0.05, 0.1, 0.15% of fiber adding ratio. After that, one hour unloading fire test was conducted, and then spalling appearance and spalling degree of specimens was examined. Test showed that a specimen made with high blaine of cement(H) improved early strength but exhibited similar value to a specimen made with low blaine(L) at the age of 28 days, thus indicating comparable spalling appearance. In conclusion, spalling easily occur in higher strength and smaller particle shape of cement and mineral admixture.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.65-70
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• 2004

The purpose of this study is to offer the basic information of waterproofing admixture of powder for field application. Through before study and fly ash in mortar, Various properties as fly ash ratio in concrete were checked. According to the experimental result, it was shown that proper Waterproofing admixture of powder increased by cement weight in concrete was generally positive effort to flowing, compressive strength, suction ratio of water, length of ratio. So if Waterproofing admixture of powder il well done quality considered as good in application of concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.178-179
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• 2019

The purpose of this study was to investigate the possibility as mineral admixture of agriculture by-product. XRD and XRF analysis were performed on rice straw ashes at various combustion temperatures to identify chemical compositions. Also to evaluate properties of pozzolanic reaction, pH change method was tested.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.527-535
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• 2001

The watertight property of concrete was examined, that is affected by the sort of self waterproofing admixture and the change of the addition ratio of admixture. Various self waterproofing admixtures were made by changing the mixing ratio of silica fume, zinc stearate and silica sand. The result showed as follows. As the adding ratio of self waterproofing admixture increases, the fluidity is increased and the setting time is delayed. While compressive strength of concrete with self waterproofing admixture A which is currently using is increased until the adding ratio of self waterproofing admixture reached 18kg/㎥ and decreased over 24 kg/㎥, that with self waterproofing admixture B, C and D which are developed are higher than that of A. Absorption is decreased as the adding ratio of self waterproofing admixture and the increasing of age in concrete. Especially, when self waterproofing admixture has a lot of zinc stearate, absorption is decreased manifestly. The property of permeability is similar to that of absorption; permeability is decreased as the adding ratio of self waterproofing admixture and the increasing of age in concrete. Consequently, when the ratio of silica fume, zinc stearate and silica sand in self waterproofing admixture is 1 : 2 : 1 and addition ratio of self waterproofing admixture is 6kg/㎥, the high quality concrete is obtained comparing to the concrete with existent self waterproofing admixture.

• Computers and Concrete
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• v.33 no.4
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• pp.471-479
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• 2024

In urban areas, appropriate backfilling design is necessary to prevent surface subsidence and subsurface cavities after excavation. Expandable foam grout (EFG), a mixture of cement, water, and an admixture, can be used for cavity filling because of its high flowability and volume expansion. EFG volume expansion induces a porous structure that can be quantified by the entrapped air content. This study observed the unit weight variations in the EFG before and after expansion depending on the various admixture-cement and water-cement ratios. Subsequently, the air content before and after expansion and the gravimetric expansion ratios were estimated from the measured unit weights. The air content before expansion linearly increased with an increase in the admixture-cement ratio, resulting in a decrease in the unit weight. The air content after the expansion and the expansion ratio increased nonlinearly, and the curves stabilized at a relatively high admixture-cement ratio. In particular, a reduced water-cement ratio limits the air content generation and expansion ratio, primarily because of the short setting time, even at a high admixture-cement ratio. Based on the results, the relationship between the maximum expansion ratio of EFG and the mixture ingredients (water-cement and admixture-cement ratios) was introduced.

• International Journal of Concrete Structures and Materials
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• v.2 no.1
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• pp.41-48
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• 2008

This study investigates the spalling properties of high strength concrete designed with various types of mineral admixture and diverse content ratios of polypropylene (PP) fiber. Experimental factors considered in series I are four pozzolan types of mineral admixture and series II consists of three shrinkage reducing types of mineral admixture. PP fiber was added 0.05, 0.10 and 0.15vol. % in each mixture of series I and series II, so that totally 27 specimens including control concretes in each series were prepared. Test results showed that the increase of fiber content decreased the slump flow of fresh concrete and increased or decreased the air content depending on the declining ratio of slump flow. For the properties of compressive strength, all specimens were indicated at around 50 MPa, which is high strength range; especially all specimens in series II were 60 MPa. Fire test was conducted in standard heating curve of ISO 834 with ${\phi}100{\times}200\;mm$ size of cylinder moulds for 1 hour. The specimens incorporating silica fume exhibited severe spalling and most specimens without the silica fume could be protected from the spalling occurrence in only 0.05vol % of PP fiber content. This fire test results demonstrated that the spalling occurrence in high strength concrete was not only affected by concrete strength related to the porosity of microstructure but also, even more influenced by micro pore structure induced by the mineral admixtures.