• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.86-93
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• 2020

Shotcrete concrete is generally used in the form of ready-mixed concrete products using type I ordinary portland cement(hereinafter referred to as OPC) and about 5% of accelerator mixed separately in the field. In this study, we tested the effect of addition of slag powder(SP) and limestone powder(LSP) on a penetration resistance, compressive strength of binder for shotcrete using calcium aluminate type accerlerator. And we analysed hydrates and pore structure effects on mortar performance. In the future, it is expected to be useful for manufacturing optimized composite cement as a binder for shotcrete.

• Composites Research
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• v.25 no.4
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• pp.110-116
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• 2012

Recently, the development and field applications of Ternary Blended Cement(TBC), where blast furnace slag and fly ash are recycled in Ordinary Portland Cement(OPC) in order to obtain improvements in the durability and heat of hydration reduction performance in large scale civil structures, have been increasing. Also, there are continuing efforts by construction companies to reduce the construction time with the aim of reducing construction costs. Therefore, there is a need to improve the performance of TBC, which has a relatively slow early strength development. In order to improve the early strength of TBC mortar, the compressive strength, SO3 content, and SEM analysis was determined in this study on mortar with the fineness and content of blast furnace slag and anhydrite regulated. As a result, to secure the early strength of TBC mortar, using blast furnace slag with a fineness of approximately $4,200cm^2/g$, adding 3.5% anhydrite with a fineness of approximately $10,000cm^2/g$, and managing the $SO_3$ content to roughly 3.72% was found to provide the most outstanding early strength properties.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.214-221
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• 2018

In this paper, the effects of ferronickel slag powder and admixture on the strength of VR sewer pipe were analyzed. the substitution rate was tested as a variable, and the strength development was studied through the flexural strength, compressive strength and using SEM microscopic analysis. bending strength, compressive strength results and micro analysis using SEM showed the correlation in each case. the substitution rates were 20% and 30% relative to the mass of the OPC respectively, and were substituted according to a constant ratio of ferronickel slag fine powder and mixture. when the substitution ratio was 20%, the strength development was excellent. also, bending strength and compressive strength were the best when the ferronickel slag fine powder, quicklime, gypsum and calcium chloride were used as the admixture, dense microstructural patterns appeared. the possibility of progressive strength development is shown after 28 days.

• Journal of Powder Materials
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• v.16 no.5
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• pp.326-335
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• 2009

Fe based (Fe$_{68.2}$C$_{5.9}$Si$_{3.5}$B$_{6.7}$P$_{9.6}$Cr$_{2.1}$Mo$_{2.0}$Al$_{2.0}$) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The Fe-based amorphous powders and the Fe-Cu composite powders were compacted by a spark plasma sintering (SPS) process. Densification of the Fe amorphous-Cu composited powders by spark plasma sintering of was occurred through a plastic deformation of the each amorphous powder and Cu phase. The SPS samples milled by AGO-2 under 500 rpm had the best homogeneity of Cu phase and showed the smallest Cu pool size. Micro-Vickers hardness of the as-SPSed specimens was changed with the milling processes.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.111-112
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• 2016

Lately, In case of domestic fire situation, Suffocation due to inflammables has shown higher than direct disaster of the fire among the statistics of death caused by disaster. According to study, Lightweight Hybrid Panel as using the inner or outer wall is made with Polysilicon of the inorganic material, PA and vermiculite, so we make progress to performance experiment and review the density, thermal conductivity properties.

• Steel and Composite Structures
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• v.45 no.6
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• pp.877-894
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• 2022

Geopolymer concrete (GPC) has emerged as a feasible choice for construction materials as a result of the environmental issues associated with the production of cement. The findings of this study contribute to the development of machine learning methods for estimating the properties of eco-friendly concrete to help reduce CO₂ emissions in the construction industry. The compressive strength (f_c) of GPC is predicted using artificial intelligence approaches in the present study when ground granulated blast-furnace slag (GGBS) is substituted with natural zeolite (NZ), silica fume (SF), and varying NaOH concentrations. For this purpose, two machine learning methods multi-layer perceptron (MLP) and radial basis function (RBF) were considered and hybridized with arithmetic optimization algorithm (AOA), and grey wolf optimization algorithm (GWO). According to the results, all methods performed very well in predicting the f_c of GPC. The proposed AOA - MLP might be identified as the outperformed framework, although other methodologies (AOA - RBF, GWO - RBF, and GWO - MLP) were also reliable in the fc of GPC forecasting process.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.55-56
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• 2022

As global warming becomes serious, research is continuously being conducted to reduce CO2 emissions. Among building materials, the carbon emission of cement is so high that it accounts for 6.8% of the carbon emission of the entire industry. Studies replacement of cement with blast furnace slag and fly ash are steadily increasing. In addition, efforts are being made to reduce air pollution due to increased damage caused by increased concentrations of harmful substances such as fine dust and heavy metals in the air. There is an increasing number of studies that enable adsorption by mixing adsorbents into building materials. This study reviewed the strength properties to make an adsorbable non-cement finishing material by mixing tourmaline, an adsorbent, based on the non-cement composite, and confirmed that the strength decreases as the replacement ratio increases.

• Journal of Powder Materials
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• v.16 no.5
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• pp.316-325
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• 2009

Fe based (Fe$_{68.2}$C$_{5.9}$Si$_{3.5}$B$_{6.7}$P$_{9.6}$Cr$_{2.1}$Mo$_{2.0}$Al$_{2.0}$) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The experiment results show that the as-prepared Fe amorphous powders less than 90 $\mu$m in size has a fully amorphous phase and its weight fraction was about 73.7%. The as-atomized amorphous Fe powders had a complete spherical shape with very clean surface. Differential scanning calorimetric results of the as-atomized Fe powders less than 90 $\mu$m showed that the glass transition, T$_g$, onset crystallization, T$_x$, and super-cooled liquid range $\Delta$T=T$_x$-T$_g$ were 512, 548 and 36$^{\circ}C$, respectively. Fe amorphous powders were mixed and deformed well with 10 wt.% Cu by using AGO-2 high energy ball mill under 500 rpm.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.243-251
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• 2022

The purpose of this study is to investigate experimentally the effect of polyethylene fibers with different tensile strength and aspect ratio on the properties of cementless composite. Three types of mixtures according to the types of polyethylene fibers and water-to-binder ratio were prepared and density, compressive strength and tension tests were performed. Test results showed that the mixture reinforced by polyethylene fiber with a low tensile strength by 10 % and a high aspect ratio by 8.3 % had a high tensile strain capacity by 11.7 %, a high toughness by 12.4 %, and a low crack width by 9.1 %. It was also observed that high tensile strain capacity and better cracking pattern could be achieved by increasing the water-to-binder ratio of composite although its strength is low.

• Journal of the Korea Institute of Building Construction
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• v.18 no.2
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• pp.109-115
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• 2018

Since the current method of SCW cement milk pouring method uses one to one ratio of cement milk with OPC, there are some problems such as drying shrinkage, increased cost, difficulty of controlling mix proportions for various conditions of applied soil, and precipitation of $Cr^{6+}$ due to the excessively used cement. Specifically, in aspect of sustainability issues of cement manufacturing, the consumption of cement should be reduced. Hence, in this research, as a replacement of cement for SCW method, blast furnace slag with sulfate or alkali as a stimulant, and expansive admixture were used. By using blast furnace slag as a hardening composite of SCW, there are many advantages such as free controllable mix proportions, rapid setting time with less mud occurrence, less cost with less energy for mixing, constant strength development, and less precipitation of $Cr^{6+}$. Regarding the alternative composites for SCW, in this research, durability and chloride resistance were evaluated.