• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.3
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• pp.41-47
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• 2009

Post-tensioned concrete pavement(PTCP) was developed to built long-span concrete pavement(120 m span) and to maintain long-term service life(over 40 years) of concrete pavement. In the present study, research for high-durable concrete was conducted to utilize the advantage of PTCP construction method efficiently. First of all, 20% of fly ash(by binder weight) was replaced to control alkali silica reaction. Second, silica fume was applied to improve the water-permeability and early-age strength. Results of tests for mechanical properties, water-permeability resistance, and surface-scaling resistance of ternary blended cement concrete showed that the early-age strength was improved significantly with addition of silica fume. The water-permeability resistance was improved from "Low" to "Very Low"(ASTM C 1202). However, surface-scaling resistance was decreased with an increase of silica fume, therefore, content of silica fume should be kept in less than 5%(by binder weight) to assure field application considering durability. The results of air-void analysis showed that durability factors were improved since spacing factors were estimated as 250$\pm$15 micron in adjusted mixtures.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.307-312
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• 1999

The purpose of this study is to ascertain the strength properties of water-permeable concrete with redispersible polymer powder, silica fume and polypropylene fibers. The water-permeable concrete using rediapersibel polymer powder with a water-cement ratio of 25%, polymer-cement ratios of 0 to 10%, silica fume contents of 0 to 10% and fiber contents of 0 to 1.5% are prepared, and tested for flexural strength, compressive strength and water permeability. From the test results, improvements in the strength properties of the water-permeable concrete due to the addition of the redispersible polymer powder, silica fume and fibers are discussed. It is concluded from the test results that the superior flexural and compressive strengths of water-permeable concretes are obtained at a propylene fiber content of 1.0% with a void filling ratio of 50%. And, the water-permeable concrete having a flexural strength of 15.6~28.4kgf/$\textrm{cm}^2$, a compressive strength of 63.5~120.6kgf/$\textrm{cm}^2$, and a coefficient of permeability of 1.14~1.70cm/s at a void filling ratio of 30% can be prepared. Also water-permeable concrete having a flexural strength of 35.6~57.9kgf/$\textrm{cm}^2$, a compressive strength of 164.0~290.0kgf/$\textrm{cm}^2$, and a coefficient of permeability of 0.19~1.04cm/s at a void filling ratio of 50% can be prepared in the consideration of the mix proprotioning factors.

• Computers and Concrete
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• v.31 no.4
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• pp.327-335
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• 2023

The most popular building material, concrete, is intrinsically linked to the advancement of humanity. Due to the ever-increasing complexity of cementitious systems, concrete formulation for desired qualities remains a difficult undertaking despite conceptual and methodological advancement in the field of concrete science. Recognising the significant pollution caused by the traditional cement industry, construction of civil engineering structures has been carried out successfully using Geopolymer Concrete (GPC), also known as High Performance Concrete (HPC). These are concretes formed by the reaction of inorganic materials with a high content of Silicon and Aluminium (Pozzolans) with alkalis to achieve cementitious properties. These supplementary cementitious materials include Ground Granulated Blast Furnace Slag (GGBFS), a waste material generated in the steel manufacturing industry; Fly Ash, which is a fine waste product produced by coal-fired power stations and Silica Fume, a by-product of producing silicon metal or ferrosilicon alloys. This result demonstrated that GPC/HPC can be utilised as a substitute for traditional Portland cement-based concrete, resulting in improvements in concrete properties in addition to environmental and economic benefits. This study explores utilising experimental data to train artificial neural networks, which are then used to determine the effect of supplementary cementitious material replacement, namely fly ash, Ground Granulated Blast Furnace Slag (GGBFS) and silica fume, on the compressive strength, tensile strength, and modulus of elasticity of concrete and to predict these values accordingly.

• International Journal of Highway Engineering
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• v.7 no.3 s.25
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• pp.31-42
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• 2005

This study evaluates the physical mechanical properties, durability and sound absorbtion of porous concrete for pavement according to content of silica fume and steel fiber to elicit the presentation of data and the way to enhance its function for the practical field application of porous concrete as a material of pavement. The results of the test indicate that in every condition, the void ratio and the coefficient of water permeability of porous concrete for pavement satisfy both the domestic standards and proposition values. Among the properties of strength, the compressive strength satisfies the standards in the specification of Korea National Housing Corporation as for every factor of mixture but in the case of the flexural strength, more than 0.6vol.% of steel fiber satisfied the Japan Concrete Institute proposition values. The mixture of silica fume and steel fiber presents the excellent intensity, though. The case when silica fume and steel fiber are used simultaneously presents the strongest durability because the durability shows the similar tendency to the dynamic characteristics. The case when 10wt.% of silica fume and 0.6vol.% of steel fiber are used at the same time shows that the loss rate of mass by Cantabro test became 27% better and freeze-thaw resistance became 60% better. As for the characteristics of sound absorption of porous concrete for pavement, Noise Reduction Coefficient is 0.48 to prove that it possesses almost 50% sound absorption.

• Journal of the Korean Ceramic Society
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• v.39 no.6
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• pp.540-549
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• 2002

In this work, the hydration behaviour of portland cement pastes containing fly ash, blast-furnace slag and silica fume is investigated by Impedance Spectroscopy(IS). As fly ash or blast-furnace slag was added to portland cement, the values of R$_{t(s+1)}$ and R$_{t(s+1)}$ were decreased in the early hydration period. It showed that hydration of cement containing blending components was slower than it of the reference cement paste with the same W/C ratio. However, the cement paste containing silica fume had a large value of R$_{t(s+1)}$ and R$_{t(int)}$due to very rapid pozzolanic reactivity of silica fume in the hydration time. In OPC-fly ash system, a characteristic plateau region appeared between straight-line and semicircle. The plateau region continued to grow in range with the content of fly ash and the hydration time.

• Advances in concrete construction
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• v.12 no.6
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• pp.479-490
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• 2021

Present research is mainly focused on, microstructural and durability analysis of Graphene Oxide (GO) in Wollastonite (WO) induced cement mortar with silica fume. The study was conducted by evaluating the mechanical properties (compressive and flexural strength), durability properties (water absorption, sorptivity and sulphate resistance) and microstructural analysis by SEM. Cement mortar mix prepared by replacing 10% ordinary portland cement with SF was considered as the control mix. Wollastonite replacement level varied from 0 to 20% by weight of cement. The optimum replacement of wollastonite was found to be 15% and this was followed by four sets of mortar specimens with varying substitution levels of cementitious material with GO at dosage rates of 0.1%, 0.2%, 0.3% and 0.4% by weight. The results indicated that the addition of up to 15%WO and 0.3% GO improves the hydration process and increase the compressive strength and flexural strength of the mortar due to the pore volume reduction, thereby strengthening the mortar mix. The resistance to water penetration and sulphate attack of mortar mixes were generally improved with the dosage of GO in presence of 15% Wollastonite and 10% silica fume content in the mortar mix. Furthermore, FE-SEM test results showed that the WO influences the lattice framework of the cement hydration products increasing the bonding between silica fume particles and cement. The optimum mix containing 0.3% GO with 15% WO replacement exhibited extensive C-S-H formation along with a uniform densified structure indicating that calcium meta-silicate has filled the pores.

• 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.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.707-714
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• 2001

This paper presents the fundamental study on rational manu(acture of Very High Strength(VHS) concrete using industrial by-products as like silica fume, slag and fly ash. In this study, we had tested various mixing cases to manufacture the VHS concrete(target compressive strength : over 1,000 kgf/$cm^{2}$) which is easily workable (target slump flow : 60$\pm$l0cm), The main variables studied are; 1) test variables to find the optimum replacement ratio of mineral admixture, 2) test variables to find a rational water-binder ratio, a proper binder content, 3) test variables to find the method for reduction of slump loss, 4) test variables to know the influence of air entrainment on frost resistance. From the test results, it is concluded that the rational mix design can be made by using 40% slag, 10% silica fume, and water reducing agent(slump loss reduction type). We found that it is unnecessary to entrain air for freeze-thawing resistance.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.161-166
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• 1994

Production of high strength concrete requires a low water-cement ratio and this leads to the high cement content. Mineral admixture like fly ash(FA) is often cheaper than ordinary portland cement(OPC) and this factor in combination with possible improvement in workability and moderation of the heat evolution of the cement-rich mixes tends to encourage its use. The other mineral admixture that its use has been widly advocated is silica fume that increases compressive strength due to its pozzolanic reaction. The objective of this study is to assess the contribution of mineral admixtures(FA, SF) to the workability and the strength of concrete with low water-binder ratios. In this experimental study that investigates and analyzes the properties of fresh concrete, it is presented that using admixtures like flysh and silica fume as binding material increases properties of high strength flowing concrete having very low water cementitious ratios of 0.25 and 0.30.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.84-87
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• 1995

Production of high strength concrete requires a low water-cement ratio and this leads to the high cement content. Mineral admixture like fly ash(FA) is often cheaper than ordinary portland cement(OPC) and this factor in combination with possible improvement in workability and moderation of the heat evolution of the cement-rich mixes tends to encourage its use. The other mineral admisture that its use has been widly advocated is silica fume that increases compressive strength due to its pozzolanic reaction. The objective of this study is to assess the contribution of mineral admixtures(FA, SF) to the workability and the strength of concrete with low water-binder ratios. In this experimental study that investigates and analyzes the properties of fresh concrete. it is presented that using admixtures like flyash and silica fume as binding material increases properties of high strength flowing concrete having very low water cementitious ratios of 0.25 and 0.30.