• Computers and Concrete
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• v.30 no.6
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• pp.393-407
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• 2022

Due to the enormous cement content, pozzolanic materials, and the use of different aggregates, sustainable controlled low-strength material (CLSM) has a higher material cost than conventional concrete and sustainable construction issues. However, by selecting appropriate materials and formulations, as well as cement and aggregate content, whitethorn costs can be reduced while having a positive environmental impact. This research explores the desire to optimize plastic properties and 28-day unconfined compressive strength (UCS) of CLSM containing powder content from unprocessed-fly ash (u-FA) and recycled fine aggregate (RFA). The mixtures' input parameters consist of water-to-cementitious material ratio (W/CM), fly ash-to-cementitious materials (FA/CM), and paste volume percentage (PV%), while flowability, bleeding, segregation index, and 28-day UCS were the desired responses. The central composite design (CCD) notion was used to produce twenty CLSM mixes and was experimentally validated using MATLAB by an Artificial Neural Network (ANN). Variance analysis (ANOVA) was used for the determination of statistical models. Results revealed that the plastic properties of CLSM improve with the FA/CM rise when the strength declines for 28 days-with an increase in FA/CM, the diameter of the flowability and bleeding decreased. Meanwhile, the u-FA's rise strengthens the CLSM's segregation resistance and raises its strength over 28 days. Using calcareous powder as a substitute for cement has a detrimental effect on bleeding, and 28-day UCS increases segregation resistance. The response surface method (RSM) can establish high correlations between responses and the constituent materials of sustainable CLSM, and the optimal values of variables can be measured to achieve the desired response properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.9-10
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• 2015

Waste Concrete Powder will be generated during the manufacture of construction waste as recycled aggregate Waste concrete. The main component of the waste concrete Powder is a silica-based composition 51% SiO₂, waste concrete cement-based composition Al₂O₃ 10%, CaO 26% component are contained. The material is silica sand of PHC piles should experiment by replacing the Waste Concrete Powder. The compressive strength results are as follows. 25% when the Silica was replaced 32.5Mpa, when 50% have replaced 43.4Mpa, when 75% have replaced 45.3Mpa was measured. Compared with the non-replaced test sample it appears that the strength increases. Therefore, it is determined that the practical use of the PHC piles by replacing silica via this experiment is possible.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.389-394
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• 2017

The aim of the research is providing the application method of recycled materials to manufacture the low costed eco-friend block at currently operated concrete block plant. In this research, based on the previous research results on three types of slag cement with illite, desulfurized gypsum, and wasted refractory products, the actual block product was manufactured by the currently operated plant facility and evaluated their properties to suggest the optimal proportions. As an experimental results, in aspect of compressive strength, absorption ratio, freezing resistance, and pH, type III slag incorporating 5% desulfurized gypsum with 1% replaced illite as an aggregate could be suggested as am optimal proportion. In additionally, considering the high cost of the illite, it can be considered as an optimal proportion that type III slag incorporating 5% desulfurized gypsum for binder.

• Journal of the Korea Institute of Building Construction
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• v.14 no.1
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• pp.54-60
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• 2014

The purpose of this study is to examine whether cementitious powder separated from waste concrete can be used as an alternative raw material to limestone and reduce the usage of natural resource (limestone) and $CO_2$ emission based on recycling cementitious powder from waste concrete. Experiments actually analyzed the chemical composition of cementitious powder and performed hyperthermia analysis, measurement of free CaO and XRD analysis to measure the degree of recovery of hydration in the model of cementitious powder manufactured based on chemical composition. These were performed in each cementitious powder model at different calcination temperatures such as $900^{\circ}C$, $1200^{\circ}C$, $1300^{\circ}C$, $1400^{\circ}C$ and $1450^{\circ}C$. Through the experiments, it was found that the recovery of hydration was at a level which can be used as the alternative raw material for limestone, but the replacement ratio was directly affected by the degree of mixing of fine aggregate in less than $150{\mu}m$, which cannot be separated from cementitious powder. It was shown that there was no difference in the production of compounds involved in hydration at calcination temperatures of $1200^{\circ}C$ or higher. Therefore, to pursue the replacement of limestone and reduction of greenhouse gas by recycling cementitious powder, the development of technology to efficiently separate aggregate fine powder is required.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.465-474
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• 2022

Research on the recycling of waste concrete has been conducted mainly focusing on the production of high-quality recycled ag g reg ate, and as a result, standards and specifications for recycled ag g reg ate have been established. However, in the case of waste concrete powder, although a lot of research on its utilization has been conducted in Korea, an innovative technology leading to commercialization has not yet been announced. Recently, research on technology using waste concrete powder as a raw material for clinker or cement has been actively conducted in major overseas advanced countries. This study investigated the overseas cases with regard to high value-added recycling technology and commercialization trend of waste concrete powder for carbon neutrality in cement and concrete industries. A number of studies have reported that it is essential to completely separate the aggregate and hydrated cement paste fraction for recycling of waste concrete powder. Also in major foreig n countries such as EU and USA, commercialization and standardization of using waste concrete powder as a raw material for clinker or a additive for cement are now in progress beyond the R&D stage. Therefore, Research and standardization for recycling of waste concrete powder should be urgently carried out from the perspective of carbon neutrality in Korea.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.68-75
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• 2006

The total production of the smelted copper reaches 450,000 tons per year, and the production of copper-related goods grows year by year owing to the extension of facilities and the development of production techniques. On the other hand, the volume of slag discharges by-produced at the time of copper smelting process is also on trend of increase. The by-produced copper smelting slag amounts to 700,000 tons a year, which is one and half times of the total smelted copper production. Accordingly nobody disagrees that comprehensive researches on how to deal with and how to reuse the accumulated smelting copper slag have to be encouraged. Even though the possible uses of the copper smelting slag have being made on various levels at present as materials for iron powder cement, sand-blasting and fire-proofing rock wool, but a considerable volume of the slag is abandoned as unnecessary by burying or piling up in careless in the open ground.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.48-55
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• 2022

This study uses the recovered water as mixing water and artificial lightweight aggregate pre-wetting water as part of a study to increase the recycling rate and reduce greenhouse gas of the ready-mixed concrete recovered during the concrete transport process, and cement fine powder of blast furnace slag(BFS) and fly ash(FA). The engineering characteristics of the three-component lightweight aggregate mortar used as a substitute were reviewed. For this purpose, the flow, dry unit mass, compressive strength, drying shrinkage, neutralization depth, and chloride ion penetration resistance of the three-component lightweight aggregate mortar were measured. When used together with the formulation, when 15 % of BFS and 5 % of FA were used, it was found to be positive in improving the compressive strength and durability of the mortar.

• Advances in concrete construction
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• v.11 no.3
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• pp.239-253
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• 2021

The behavior of concrete containing waste glass as a replacement of cement or aggregate was studied previously in the most of researches, but the present investigation focuses on the recycling of waste glass powder as a substitute for silica fume in high strength concrete (HSC). This endeavor deals with the efficiency of using waste glass powder, as an alternative for silica fume, in the flexural capacity of HSC beam. Thirteen members with dimensions of 0.3 m width, 0.15 m depth and 0.9 m span length were utilized in this work. A comparison study was performed considering HSC members and hybrid beams fabricated by HSC and conventional normal concrete (CC). In addition to the experiments on the influence of glass powder on flexural behavior, numerical analysis was implemented using nonlinear finite element approach to simulate the structural performance of the beams. Same constitutive relationships were selected to model the behavior of HSC with waste glass powder or silica fume to show the matching between the modeling outputs for beams made with these powders. The results showed that the loading capacity and ductility index of the HSC beams with waste glass powder demonstrated enhancing ultimate load and ductility compared with those of HSC specimens with silica fume. The study deduced that the recycled waste glass powder is a good alternative to the pozzolanic powder of silica fume.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.242-243
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• 2014

In this study, industrial by-products including blast furnace slag, incineration ash and waste gypsum were used with recycled fine aggregates to manufacture the zero-cement mortar. The replacement ratio of anhydrite gypsum was fixed as 0, 10%, 20% the replacement ratio fo WA1 was fixed as 0.5% and 1.0%, respectively. It could be identified that when the replacement of gypsum was 20% and WA1 of 1.0%, the strength could be in the range of normal strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.222-223
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• 2014

In this study, industrial by-products including blast furnace slag, incineration ash and waste gypsum were used with recycled fine aggregates to manufacture the zero-cement mortar.The replacement ratio of dihydrate gypsum and anhydrite gypsum was fixed as 0 and 10%, the replacement ratio fo WA1 was fixed as 0.5% and 1.0%, respectively. It could be identified that when the replacement of gypsum was 10% and WA1 of 1.0%, the strength could be in the range of normal strength.