• 한국세라믹학회지
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• 제52권2호
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• pp.159-164
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• 2015

We manufacture artificial lightweight aggregates (ALWAs) using bottom-ash as the primary raw material. We coat the ALWA surfaces with low-melting point materials in order to enable them to bloat, which is essential to reduce the bulk density of the aggregate. Then, we sinter the prepared aggregates at 1000, 1100, and $1200^{\circ}C$ using either the direct or two-step firing schedules. Finally, we evaluate the properties of the fired samples through analyzing their bulk density, water absorption, and microstructure. The surface-modified samples result in a reduction of their bulk density by $0.3{\sim}0.4g/cm^3$ regardless of the firing method used. Based on these results, we conclude that this approach could provide a viable method for the mass-production of ALWAs from industrial waste such as bottom-ash.

• 한국환경과학회지
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• 제16권10호
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• pp.1169-1177
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• 2007

The main objective of this research was to evaluate the effects of process variables which were forming ability, flow displacement, effective stress, effective strain, fluid vector and products defects on manufactured artificial lightweight aggregate made of both incinerated sewage sludge ash and clay by means of the numerical analysis of a rigid-plastic finite element method. CATIA (3D CAD program) was used for an extrusion metal mold design that was widely used in designing aircraft, automobile and metallic molds. A metal forming analysis program (ATES Co.) had a function of a rigid-plastic finite element method was used to analyze the program. The result of extrusion forming analysis indicated clearly that a shape retention of the manufactured artificial light-weight aggregate could be maintained by increasing the extrusion ratio (increasing compressive strength inside of extrusion die) and decreasing the die angle. The stress concentration of metal mold was increased by increasing an extrusion ratio, and it was higher in a junction of punch and materials, friction parts between a bottom of the punch and inside of a container, a place of die angle and a place of die of metal mold. Therefore, a heat treatment as well as a rounding treatment for stress distribution in the higher stress concentration regions were necessary to extend a lifetime of the metallic mold. A deformity of the products could have made from several factors which were a surface crack, a lack of the shape retention and a crack of inside of the products. Specially, the surface crack in the products was the most notably affected by the extrusion ratio.

• 한국건설순환자원학회논문집
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• 제7권3호
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• pp.49-55
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• 2012

본 연구에서는 인공경량골재의 주요 물성인 밀도 및 흡수율의 성능 향상을 위하여 융제 종류 및 첨가율에 따른 밀도 및 흡수율 특성을 검토하였다. 실험결과, 화학제품의 융제 사용에 관한 특성으로, $Na_2CO_3$ 및 $CaSO_4$는 경우 낮은 소성온도에서 소성이 가능하나, 흡수율이 증가하였고, $CaCO_3$, NaOH, $Fe_2O_3$는 첨가율이 증가할수록 흡수율은 낮아졌으나, 절건밀도가 높아지는 것으로 나타나 융제로서 부적합하였다. $Na_2SO_4$의 사용한 경우에는 절건밀도 $1.35{\sim}1.50g/cm^3$와 상대적으로 낮은 흡수율로 융제로서 가장 적합하였다. 산업부산물의 융제 사용에 관한 특성으로 유리연마 슬러지는 절건밀도 $1.45{\sim}1.55g/cm^3$ 및 흡수율 9~12 %로 흡수율이 높게 나타났다. 고로슬래그 미분말은 첨가율이 증가할수록 밀도는 높아지고 흡수율은 낮아지는 것으로 나타났다. 산화슬래그는 첨가율 10 %에서 절건밀도 $1.46g/cm^3$, 흡수율 8,5 %로 낮은 절건밀도와 흡수율을 갖는 양질의 인공경량골재를 제조할 수 있었다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.69-74
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• 2002

Incineration method of municipal solid waste is the general method for reduction it's quantity and weight. Municipal solid waste incineration ash is classified two general types of ash : fly ash((MWFA) and bottom ash(MWBA)). MWFA containing a high degree heavy-metal may give rise to a serious environmental trouble. Therefore, this study was carried out to examine utilization of fly ash. In this study, we tried to find the recycling method of fly ash as a environmental-friendly artificial aggregate. The artificial aggregate using fly ash was tested for the various aspects, including physical properties and environmental stability. The qualities of artificial aggregate are similar to it of lightweight aggregate, and the heavy metal leaching concentration are very lower than a limitation of KSLT and EP.

• Structural Engineering and Mechanics
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• 제87권3호
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• pp.221-229
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• 2023

Urbanization and industrialization have significantly increased the amount of solid waste produced in recent decades, posing considerable disposal problems and environmental burdens. The practice of waste utilization in concrete has gained popularity among construction practitioners and researchers for the efficient use of resources and the transition to the circular economy in construction. This study employed Lytag aggregate, an environmentally friendly pulverized fuel ash-based lightweight aggregate, as a substitute for natural coarse aggregate. At the same time, fly ash, an industrial by-product, was used as a partial substitute for cement. Concrete mix M20 was experimented with using fly ash and Lytag lightweight aggregate. The percentages of fly ash that make up the replacements were 5%, 10%, 15%, 20%, and 25%. The Compressive Strength (CS), Split Tensile Strength (STS), and deflection were discovered at these percentages after 56 days of testing. The concrete cube, cylinder, and beam specimens were examined in the explorations, as mentioned earlier. The results indicate that a 10% substitution of cement with fly ash and a replacement of coarse aggregate with Lytag lightweight aggregate produced concrete that performed well in terms of mechanical properties and deflection. The cementitious composites have varying characteristics as the environment changes. Therefore, understanding their mechanical properties are crucial for safety reasons. CS, STS, and deflection are the essential property of concrete. Machine learning (ML) approaches have been necessary to predict the CS of concrete. The Artificial Fish Swarm Optimization (AFSO), Particle Swarm Optimization (PSO), and Harmony Search (HS) algorithms were investigated for the prediction of outcomes. This work deftly explains the tremendous AFSO technique, which achieves the precise ideal values of the weights in the model to crown the mathematical modeling technique. This has been proved by the minimum, maximum, and sample median, and the first and third quartiles were used as the basis for a boxplot through the standardized method of showing the dataset. It graphically displays the quantitative value distribution of a field. The correlation matrix and confidence interval were represented graphically using the corrupt method.

• 콘크리트학회논문집
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• 제21권2호
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• pp.147-152
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• 2009

본 연구는 국내에서 최초로 개발된 폐유리로 제조된 인공경량골재 (artifical lightweight aggregate: ALA)의 물리적 특성에 관한 연구를 통해 경량 모르타르 및 경량 콘크리트의 개발에 기초자료로 활용하기 위해 인공경량골재의 입도에 따른 3종류 (La, Lb, Lc)의 모르타르에 대하여 압축강도 실험, 단위질량 및 모르타르의 흡수율 실험을 실시하였다. 이상의 실험 결과, ALA의 밀도 및 단위질량은 내부의 독립기공구조로 인하여 보통골재의 50% 이하의 값을 나타냈으며, ALA를 사용한 모르타르의 흡수율시험 결과 Control 모르타르와 큰 차이가 없었다. 이는 ALA의 내부의 독립기공구조에 의한 것으로 판단된다. ALA를 사용한 모르타르의 경우 혼입률이 증가 할수록 압축강도와 휨강도는 감소하는 경향이 나타났으나, La50 모르타르를 제외한 모든 모르타르는 Control 모르타르 압축강도의 70% 이상을 나타내었다. 향후 광물질 혼화재, 물-시멘트비 의 조절에 따라 Control 모르타르와 동등한 강도가 발현 될 것이라 판단되며, 장기 내구성에 대한 검토도 함께 이루어져야 할 것으로 판단된다.

• Computers and Concrete
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• 제27권3호
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• pp.241-252
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• 2021

An experimental program was conducted to investigate the fresh properties, mechanical properties and durability characteristics of the self-compacting mortars (SCM) produced with pumice powder and Artificial Lightweight Fine Aggregate (aLWFA). aLWFA was produced by using fly ash. A total of 16 different mixtures were designed with a constant water-binder ratio of 0.37, in which natural sands were partially replaced with aLWFA and pumice powder at different volume fractions of 5%, 10% and 15%. The artificial lightweight aggregates used in this study were manufactured through cold bonding pelletisation of 90% of class-F fly ash and 10% of Portland cement in a tilted pan with an ambient temperature and moisture content. Flowability tests were conducted on the fresh mortar mixtures beforehand, to determine the self-compacting characteristics on the basis of EFNARC. To determine the conformity of the fresh mortar characteristics with the standards, mini-slump and mini-V-funnel tests were carried out. Hardened state tests were conducted after 7, 28 and 56 days to determine the flexural strength and axial compressive strength respectively. Durability, sorptivity, permeability and density tests were conducted at the end of 28 days of curing time. The test results showed that the pumice powder replacement improved both the fresh state and the hardened state characteristics of the mortar and the optimum mixture ratio was determined as 15%, considering other studies in the literature. In the aLWFA mixtures used, the mechanical and durability characteristics of the modified compositions were very close to the control mixture. It is concluded in this study that mixtures with pumice powder replacement eliminated the negative effects of the aLWFA in the mortars and made a positive contribution.

• 한국결정성장학회지
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• 제18권3호
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• pp.125-130
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• 2008

소형 전기로 및 이동장치가 있는 시뮬레이터를 사용하여 로타리킬른에서 생산되는 인공경량골재의 물성을 예측 할 수 있다면 대규모 로타리 킬른을 사용하여 인공경량골재 시제품 생산할 때 필요한 물자와 시간을 대폭 절감할 수 있다. 본 실험에서는 생산될 인공경량 골재의 물성을 정확히 예측할 수 있는 시뮬레이터를 제작하여 실제 로타리 킬른에서 생산된 골재의 물성과 비교함으로써 그 유용성을 검토하고자 하였다. 골재의 물성을 예측하기 위해서 8 mm 크기의 에코 인공경량 골재를 사용하였고 시뮬레이터의 분위기를 탄소를 이용해 조절하였다. 시뮬레이터와 로타리킬른에서 소성된 골재의 비중, 흡수율, 골재의 단면의 면적을 측정하고 비교하였다. 산화 분위기와 달리 환원분위기에서 소성된 시편은 탄소량이 증가할수록 비중이 증가하였으며 흡수율은 탄소 첨가량이 증가할수록 증가하는 경향을 보였다. 소성분위기는 환원 분위기 조성을 위해 탄소분말 0.7g을 첨가하였을 때 로라리 킬른과 가장 흡사한 분위기가 형성되는 것으로 판단되며, 두 골재의 물성 역시 비슷하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 봄 학술발표회 논문집
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• pp.99-104
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• 1991

It is necessary to generalize the use for structural ALA Concrete in our country, as increasing in the need for the development of ALA and the use of ALA Concrete which is related with the diminution of the self load and foundation section of structure responding to the realistic requirement against the decrease of natural aggregate and the high-rising and large-sizing of structures. This little study, therefore intended to help in the mixing design of concrete by considering the fundamental properties of ALA Concrete used with expanded clay, which is considered by acopting the experimental factors such as unit cement content, water cement ratio and the rate of fine aggregate. By considering the results of this experiment, it has difficulty in getting expected slump with the unit water content of normal concrete because of the large absorption of lightweight aggregate, and because the weight of unit volume and specific gravity ALA Concrete are small it appears that the strength and Elastic Modulus of that are small too and that it is more ductile than normal concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.136-137
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• 2020

This study compared and analyzed the fluidity and strength characteristics of mortar using the recycling water, indicates strong alkali properties, as pre-wetting water of artificial light aggregate to increase usage ratio of recycling.