• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.327-328
• /
• 2009

This study was conducted to substitute blast furnace slag powder and gypsum activator for the purpose of improving mortar quality with fine particle cement extracted using particle size screening in the cement manufacturing process. While flowability and early strength were reduced, partial compressive strength showed increase on the 28th day.

• Magazine of the Korea Concrete Institute
• /
• v.4 no.1
• /
• pp.97-106
• /
• 1992

Apparent diffusion coefficients of Cl- ions through hardened cement pastes(HCP), which were partly subs¬tituted blast furnace slag, fly ash and silicafume for ordinary Portland cement, were determined. Also. Cl- and OW concentration of pore solutions which were extracted from HCP and the capacities of the HCP to bind CI were determined. Diffusion coefficients of Cl- ions through HCP were increased with water cement ratio(WfC), but decreased with addition of the blending materials. On the contrary, Cl- and OH concentration of the pore solutions were reduced by adding the blending materials.

• Journal of the Korea Concrete Institute
• /
• v.27 no.3
• /
• pp.237-244
• /
• 2015

Entering the 20th century since the industrial revolution, the cement has been widely used in the field of construction and civil engineering due to the remarkable development of construction industry. However, result from that development, each kind of industrial by-products and waste and the carbon dioxide generated in the process of cement production cause air pollution and environmental damage so earth is getting sick now slowly. Therefore, we have to recognize importance about this. It means that the time taking specific and long-term measures have come. In this research paper, as substitution of the cement generating environmental pollution, we investigate the hydration reaction of non-Sintered Cement mortar mixed with GBFS, active stimulant of alkaline and sulphate series by using SEM and XRD, mechanical and chemical properties according to the curing method. As a result of this experiment, NSC realized outstanding strength for water curing and steam curing. It means that it has a good possibility as substitution of cement. From now on, it can be used for structure satisfying specific standard. We expect to find a substitution of outstanding cement by progressing continuous research making the best use of pros and cons according to the curing method.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.5 no.1
• /
• pp.131-138
• /
• 2010

This research intends to analyze the basic characteristics of cements(hereinafter "CC") with affordable price and particle distribution effective as hydration heat face which are discharged at the outlet of smashing process of ordinary portland cement(hereinafter "OPC") manufacturing process such as fluidity, rigidity, temporary insulation temperature increase amount etc to review the potential of developing "CC" to 3 ingredients low heat cement that substitutes fly ash and blast furnace slag(hereinafter "BS"). As a result of experiment, fluidity tended to decrease with increase in CC substitution rate, and increase with increase in FA+BS substitution rate. Air amount tended to slightly decrease with increase in CC substitution rate, and decrease with increase in FA+BS substitution rate. Condensation characteristics were such that condensation time was delayed with increase in CC and FA+BS substitution rate. As for the temperature rising amount by temporary insulation, peak temperature decreased with increase in CC substitution rate and increase in FA+BS substitution rate in general, and thereafter, temperature tended to decrease slowly. Compressive strength decreased with increase in CC and FA+BS substitution rate, and as aging goes on, long term strength was equivalent to plain or higher. By and large, when FA+BS was substituted to CC, fluidity and air amount tended to decrease, but hydration heat face showed good reduction effects, suggesting possibility of development to 3 ingredients low heat cement.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2008.11a
• /
• pp.569-572
• /
• 2008

This study carried out to evaluate the quality deviation according to Premixed and Non-Premixed cement for normal and high strength concrete using blast furnace slag and fly ash. The results of experiment are founded that concrete using premixed cement have more performance than non-premixed cement at a point of view for the quality deviations both strength and Chloride ion diffusion. Therefore, it is desirable that premixed cement should be used to decrease strength deviation in high strength concrete and durability deviation in normal strength concrete.

• Journal of the Korean Geotechnical Society
• /
• v.22 no.4
• /
• pp.31-39
• /
• 2006

An experimental investigation was carried out to evaluate the strength characteristics of low cement ratio soil stabilizer. The low cement ratio soil stabilizer has been developed by the replacement of certain part of cement with by-product pozzolanic materials such as blast furnace slag, fly ash, waste gypsum and by using activator. A series of unconfined compressive strength tests were performed to investigate and obtain high-strength composite soil stabilizer with large amounts of blast furnace slag and fly ash. Test results show that there were better properties when blast furnace slag, fly ash, waste gypsum, and activator were added in proper ratio. The replacement of certain part of cement with by-product pozzolanic materials improved the strength and pore structure properties.

• Resources Recycling
• /
• v.25 no.2
• /
• pp.49-59
• /
• 2016

Steel slag is being recycled into industrial by-products for civil generated inevitably in the seasonal course, road and cement raw materials. However, the field of recycling most of the bottom portion is concentrated in the areas that are required to take advantage of the situation in various fields taking advantage of the steel slag. But various studies to take advantage of the steel slag as aggregate for concrete made for limiting slag was a situation that most of the studies are incomplete research on the suitability of as aggregate for concrete practical relates to an expandable suppressed. In this study, the separation of the slag aggregate according to the production methods to assess the feasibility aggregate for concrete aggregates, including through Steel making slag, a total of seven kinds of steel slag aggregate. Studies show that ordinary concrete, steel slag aggregate for aggregate and on the equally to take advantage of grading, chloride content standards such as to what is lacking, although appropriate aggregate of concrete include the deployment of only in special sectors through the combination was assessed to have a very high.

• Journal of the Korea Concrete Institute
• /
• v.15 no.3
• /
• pp.400-408
• /
• 2003

Chloride ion inside concrete destroys the so-called passive film surrounding reinforcing bars inside concrete so that the so-called salt attack accelerates corrosion which is the most critical factor for durability as well as structural safety of reinforced concrete structures. Recently, as a solution of the salt attack, the ground granulated blast-furnace slag(GGBFS) have been used as binder or blended cement more extensively. In this paper, characteristics of chloride ion diffusion for the GGBFS concrete, which is known to possess better resistance to damage due to the chloride ion penetration than ordinary portland cement(OPC) concrete possesses, are analyzed and a chloride ion diffusion model for the GGBFS concrete is proposed by modifying an existing diffusion model for the OPC concrete. The proposed model is verified by comparing diffusion analysis results using the model accelerated chloride penetration test results for concrete specimens as well as field test results for an RC bridge pier. Then, an optimal resistance condition to chloride penetration for the GGBFS concrete is obtained according to degrees of fineness and replacement ratios of the GGBFS concrete. The result shows that the GGBFS concrete has better resistance to chloride ion penetration than OPC concrete has and the resistance is more affected by the replacement ratio than the degree of fineness of the GGBFS.

• Resources Recycling
• /
• v.19 no.3
• /
• pp.33-44
• /
• 2010

In this study, the possibility of utilizing carbide lime waste, obtained from the generation of acetylene process, as a alkali activator of blast furnace slag cement was investigated. The physical and chemical analysis of the carbide lime waste was studied and three types lime waste in order to investigate behaviour as alkali activator were used. Lime wastes were added 0, 10, 20 and 30 wt.% in blast furnace slag and blast furnace slag containing lime waste were added 0, 10, 30 and 50 wt.% in OPC. As a result of analysis of hydration properties, in the case of calcium hydroxide rehydrated after heat treatment at $800^{\circ}C$, it was higher hydration rate than other specimens. For the results of compressive strength test, when lime waste passed 325 mesh sieve and rehydrated calcium hydroxide were used, it was higher compressive strength than OPC from hydration 7days. At OPC50 wt.%-BFS45 wt.%-AA5 wt.% system using lime waste of 325 mesh under, the highest compressive strength appeared.

• Resources Recycling
• /
• v.19 no.5
• /
• pp.50-57
• /
• 2010

Ternary blended concrete(TBC), which contains both fly ash and granulated blast furnace slag, has an initial cost effective and is environment friendly. Furthermore, it has a lot of technical advantages such as the improvement of long term compressive strength, high workability, and the reduction of hydration heat. However, as the use and study on the performance of ternary blended concrete is limited, it is low short term compressive strength. This study was performed to evaluate the characteristics which are a long and short term compressive strengths, permeability and chemical attacks resistance of hardened high early concrete containing slag powder and fly-ash using high early strength cement(HE-TBC). Replacement rate of FA is fixed on 10% and replacement rate of slag powder are 0%, 10%, 20% and 30%. The test results showed that compressive and flexural strength of HE-TBC increased as the slag contents increased from 0% to 30% at the short term of curing. The permeability resistance of HE-TBC(fly ash 10%, blast 30%) was extremely good at the short and long terms. However, high early strength ternary blended concrete had weak on carbonation of chemical attack.