• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.21-22
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• 2021

This study incorporates fine waste glass (GS) as a replacement for natural sand (NS) in ground granulated blast furnace slag (GGBS) based alkali activated mortar (AAm). Tests were conducted on the AAm to determine the mechanical properties, apparent porosity and the durability based on its resistance to Na2SO4 5% and H2SO4 2% concentrated solutions. The study revealed that increasing GS up to 100 wt%, increased strength and decreased porosity. The lower porosity attained with the incorporation of GS, improved the resistance of mortar to Na2SO4 and thus increasing durability. However, the durability of mortar to H2SO4 solution was negatively impacted with the further reduction of porosity observed with increasing GS above 50 wt.% believed to be caused by the stress induced as a result of expansive reaction products created when the mortar reacted with acid.

• Resources Recycling
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• v.12 no.5
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• pp.16-22
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• 2003

Lightweight aggregate for concrete was manufactured from recycling the waste PET bottles (PET Bottle Lightweight Aggregate, LAPET). The qualities of LAPET and its mortar were investigated. Specific gravity and unit weight of LAPET was very low in comparison with river sand like as 1.39, 844 kg/㎥ respectively. In addition, compressive strength of concrete significantly decreased because of specific gravity of aggregate decreased with increases in containing ratio. When LAPET was contained to 25% and 50％ of river sand, compressive strength of concrete at 28 days was indicated more 30MPa. Most of LAPET was generally showed to round shape and fluidity of mortar increased significantly due to sleeking the surface texture of LAPET. On the other hand, capillary absorption of mortar with LAPET was greatly increased in comparison with that of mortar without LAPET because of LAPET was composed of singular gradation. Absorption of LAPET was 0％ because the interior structure of LAPET consists of PET like as organic high polymer. Therefore the fault of normal lightweight aggregate, absorption, will be improved. It could expect several advantages that the pollution of environment will be previously prevent and the waste resources could be recycled if LAPET is reused as aggregate for Lightweight concrete.

• Journal of the Korea Institute of Building Construction
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• v.15 no.2
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• pp.161-167
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• 2015

Nowadays, all the world face to the global warming problems due to the emission of $CO_2$. From the previous studies, recycled aggregates were used as an alkali activator in blast furnace slag to achieve zero-cement concrete, and favorable results of obtaining strength were achieved. In this study, gypsum and incineration waste ash were used as the additional alkali activation and effects of the gypsum and incineration waste ash to enhance the performance of the mortar were tested. Results showed that although the replacement ratio of 0.5% of incineration waste ash and 20% of anhydrous gypsum resulted in the low of mortar at the early age, while it improved the later strength and achieved the similar strength to that of conventional mortar (at 91 days).

• Advances in concrete construction
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• v.15 no.3
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• pp.149-159
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• 2023

Water glass (WG) and sodium sulfate (SS) were used to prepare polymeric aluminum chloride residue cement mortar (PACRM) by single and compound blending with polymeric aluminum chloride waste residue, respectively. The structural strength and textural characteristics examinations showed that PACRM consistency increased by incorporating WG, but decreased by incorporating SS. When WG and SS were compounded, the mortar consistency initially rose before falling. The compressive strength of PACRM increased and then decreased as WG was increased. The mechanical properties of PACRM were better enhanced by SS than WG, showing no strength deterioration. The main reason for the improved mechanical properties of polymeric aluminum chloride waste residue in the presence of activators is the increased precipitation of reactive substances, such as C-S-H gels, calcium silica, and Ca(OH)₂. The density of the specimens with PACRM and the degree of aggregation of hydration products were significantly enhanced by generating more hydration products in the mortar. Further, the cracks and pores were significantly reduced, and the matrix structure was continuous and dense at 5% SS doping and 3% compound doping.

• Magazine of RCR
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• v.14 no.3
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• pp.17-25
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• 2019

• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.213-220
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• 2001

Incorporation of wastes glass aggregate in mortar may cause crack and this may result in the strength reduction due to alkali-silica reaction(ASR) and expansion. The purposes of this study were to investigate the properties of alkali-silica expansion and strength loss through a series of experiments which had a main experimental variables such as waste glass aggregate contents, glass colors, fiber types, and fiber contents. The steel fibers and polypropylene fibers were used for constraining the ASR expansion and mortar cracking. From the result, green waste glass was more suitable than brown one because of low expansion. And in this accelerated ASTM C 1260 test of waste glass, pessimum content can not be found. Also, when used the fibers with waste glass, there is an effect on reduction of expansion and strength loss due to ASR between the alkali in the cement paste and the silica in the waste glass. Specially, adding 1.5 vol.% of steel fiber to 20% of waste glass, the expansion ratio was reduced by 40% and flexural strength was developed by up to 110% comparing with only waste glass(80$\^{C}$ H$_2$O curing).

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.228-231
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• 2004

The purpose of this study evaluates possibilities of waste phosphogypsum into concrete by steam curing admixture. The waste phosphogypsums were classified into 4 forms(Dihydrate, $\beta-Hemihydrate$, III-Anhydrite and II-Anhydrite) which were changed to in low temperature of calcination. Also, various admixtures were made of waste phosphogypsum(PG) and pozollanic fine powderers (Fly-ash, Blast Furnace Slag), and the basic properties of the cement mortars incorporating with these admixtures were examined and analyzed under a verity of experimental conditions. As a result, III-Anhydrite, these is similar to II-Anhydrite from compressive strength and are great in the effect of strength improvement. also, it was proved that specimens made on type III-Anhydrite of waste phosphogypsum and blast furnace slag increased on the compressive strength of cement mortar. Therefore, III-Anhydrite phosphogypsum calcined at lower temperature could be used as steam curing admixture for concrete 2th production.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.81-87
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• 2003

The purpose of this study is the development of a recycling process to recover the hydrated ability of cement hydrate which accounts for a large proportion of cementitious powder by concrete waste in order to recycle cementitious powder by concrete waste as recycle cement. Therefore, after having theoretical consideration based on the properties of high-heated concrete, we consider the properties of hydration of cementitious powder in hardened mortar under various temperature conditions. As a result of experiment, it is revealed that an effective development of recycling cement is possible since the cementitious powder by concrete waste recovers a hydraulic property during burning at $600^{\circ}C$ or $700^{\circ}C$. And it is shown that the fluidity of mortar decreases rapidly as the burning temperature of recycle cement increases. however, the improved effect of fluidity is predominant if adding the additive such as fly-ash or blast furnace slag.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.112-113
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• 2021

Since natural sand is being depleted, research is being conducted to use glass similar to sand as an aggregate. When non-reusable waste glass is crushed and used as fine aggregate, it is known that alkali of cement and silica of glass react to cause an alkali aggregate reaction. The purpose of this study is to provide basic data by studying the strength according to color to use waste glass as fine aggregate. When 10% was replaced, both flexural and compressive strength showed strength values similar to those of Plain. When replaced by 20% and 30%, the 7-day intensity was higher than that of Plain. In addition, colorless glass was found to have the highest strength among glass colors. More research is expected to be needed to become a fine aggregate of waste glass.

• Journal of the Korea Institute of Building Construction
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• v.4 no.4
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• pp.79-86
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• 2004

The purpose of this study was the development of a recycling process to recover the hydraulic properties of hydration products which account for a large proportion of cementitious powder from concrete waste. This process was performed to recycle cementitious powder as recycle cement. Therefore, after the theoretical consideration of the properties of recycle process of recycled aggregates and cementitious powder, we investigated the hydraulic properties of cementitious powder under various temperature conditions in hardened mortar which was modeled on concrete waste. And we analyzed properties of chemical reactions of recycled cement with admixture materials such as Fly-Ash, Blast Furnace Slag As a result of the experiment, the most effective method to recover hydraulic properties of the cementitious powder from concrete waste was condition of burning at 700℃ for 120 minute. And it is shown that the fluidity of mortar was decreased rapidly when the burning temperature of recycle cement was increased. However, the compressive strength and fluidity were improved significantly when admixture materials such as Fly-Ash or Blast Furnace Slag was added.