• Structural Engineering and Mechanics
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• 제19권3호
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• pp.321-336
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• 2005

The structural feasibility of a variety of non-conventional sludge digesters, in the form of thin shells of revolution constructed in concrete, has formed the subject of investigation of a recent programme of research at the University of Cape Town. Such forms are usually known in the literature as "egg-shaped", and the advantages of these over conventional digesters of the wide-cylindrical type are now well-recognised: superior mixing efficiency, less accumulation of deposits at the bottom, easier removal of bottom deposits and surface crust, reduced heat losses, and so forth. With the aim of exploring the structural feasibility of various non-conventional forms for concrete sludge digesters, and making available usable analytical data and practical guidelines for the design of such thin shell structures, a number of theoretical studies have recently been undertaken, and these have covered conical assemblies, spherical assemblies and parabolic ogival configurations. The purpose of the present paper is to bring together the different analytical approaches employed in each of these studies, summarise the main findings in each case, draw comparisons among the various studied configurations with regard to structural efficiency and functional suitability, and make appropriate conclusions and recommendations.

• 콘크리트학회논문집
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• 제13권6호
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• pp.561-567
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• 2001

석산에서 부순잔골재를 생산시에는 다량의 슬러지 미립분이 배출되고 있다. 그러나, 실무현장에서는 슬러지의 일부를 매립용등에 제한적으로 사용할 뿐, 대부분은 방치되거나 무분별하게 버려지고 있어 막대한 경제적 손실과 환경오염 문제를 유발시키고 있다. 따라서 본 연구에서는 석산폐기물인 슬러지를 공장제품용 시멘트 모르타르 제조에 골재대체용 충전재로 활용하기 위하여, 골재 종류 및 모르타르 배합비 등에 미립분 혼입률을 변화시켜 시멘트 모르타르의 강도 및 흡수 특성을 검토하였다. 연구결과, 시멘트 모르타르 제품을 제조할 때 슬러지를 골재에 10% 정도 대체하여 혼입하게 되면 기존의 시멘트 모르타르 제품보다 향상된 품질의 제품이 생산될 수 있는 것이 확인되었다.

• 대한환경공학회지
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• 제35권11호
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• pp.803-808
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• 2013

본 연구의 목적은 칼슘염을 함유한 레미콘 슬러지를 이용하여 불소함유폐수를 물에 난용성인 $CaF_2$ 화합물 형태로 침전시켜 처리하는데 있어 pH, 레미콘슬러지 주입량, Seed물질 주입량, 교반속도, 교반시간의 최적 조건을 도출하고자 하는데 있다. 실험결과 레미콘 슬러지를 이용한 대상폐수의 $CaF_2$ 침전 반응에서 함수율 및 불소의 제거효율 등을 고려할 경우 최적의 pH 6, 레미콘 슬러지 주입량은 10 g/L, Seed 물질 주입량은 2 g/L, 교반속도은 100 rpm, 교반시간은 60 min으로 관찰되었다. 이 때 Seed 물질의 주입은 불소제거효율에는 영향이 없는 것으로 나타났지만 침전물의 형성이 되는 반응을 촉진시키고 플럭형성을 원활하게 하여 고액 분리가 잘 되어 함수율이 낮아지는 결과가 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.69-75
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• 1997

This studies regarding deveolpment of product system on artificial aggregate using of Paper Sludge Ash that waste production at paper-making mill. Expecially this paper discribes development of product system using centrifugal mixer plant. The skills of this product system on artificial aggregate using of Ash can be spread Fly-Ash, powder and fine aggregate (under 5mm) of waste concrete reuse.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.327-328
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• 2021

In the manufacturing process of ready-mixed concrete, quantity management directly affects the workability and strength of concrete. Therefore, water quantity is the most important management factor for water quality control of ready-mixed concrete. It can be said that the number of unit water in the mix design, the water quantity due to the surface water contained in the aggregate used, and the water quantity taking into account the concentration of sludge contained in the recycling water when using the recycling water are factors that affect the quantity management of ready-mixed concrete. In this study, as a stable quality control method of ready-mixed concrete, a quantity management method by aggregate surface water and a sludge concentration management method according to the use of recycling water were proposed. Thus, we tried to suggest an efficient quantity management method for stabilizing the quality of ready-mixed concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.118-119
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• 2021

In this study, we confirmed the basic characteristics of paste and mortar 1:1, 1:2, 1:3 composition using concrete sludge solid content for the purpose of developing a resource-recycling cement secondary products. The 1:2 mortar formulation showed the best compressive strength. The steam curing strength is superior in the order of C20, BS40, BS20 and Control. it is judged that the FA combination is not suitable.

• Computers and Concrete
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• 제16권3호
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• pp.449-466
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• 2015

This paper aims to study the local bond stress-slip behavior of reinforcing bars embedded in lightweight aggregate concrete (LWAC). The experimental variables of the local bond stress-slip tests include concrete strength (20, 40 and 60 MPa), deformed steel bar size (#4, #6 and #8) and coarse aggregate (normal weight aggregate, reservoir sludge lightweight aggregate and waterworks sludge lightweight aggregate). The test results show that the ultimate bond strength increased with the increase of concrete compressive strength. Moreover, the larger the rib height to the diameter ratio ($h/d_b$) of the deformed steel bars is, the greater the ultimate bond stress is. In addition, the suggestion value of the CEB-FIP Model Code to the LWAC specimen's ultimate bond stress is more conservative than that of the normal weight concrete.

• 한국건축시공학회지
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• 제1권2호
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• pp.146-153
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• 2001

Radical development has been made in the every field of our society for the past scores of year. Radical development of industry and lining environment has mass-produced various toxic wastes . Which comes to the fore as a serious environmental problem. The purpose of this is to suggest the optima mix design by studying the utility of a toxic waste, plated sludge as a building material and deciding the standards of quality and use of cement and evaluating the properties of mortar and concrete in which plated sludge mixed. From an experiment, compressive strength required high early strength cement or special cement. Watertightness proved to be excellent. Heavy metals, such as Cd, Pb, Cu came out below an environmental standard. Cr+6 exceeded an environmental standard under a steam curing, but came out below an environmental under a standard curing. The higher replacement rate was, the lower frost, fusion and resistance were. Thus, got better results above the goal by condition. It was possible that plated sludge was replaced and solidified to aggregate. Therefore, it is necessary to define the standards of quality on strength, replacement rate of wastes, water permeability, endurance in other to solidify plated sludge to concrete products.

• 자원리싸이클링
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• 제17권4호
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• pp.10-20
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• 2008

본 연구는 아직까지 활용실적이 적은 제지슬러지소각재를 대량으로 활용할 수 있는 방법을 도출하기 위하여 제지슬러지소각재를 시멘트의 대체재로 사용하고자 하였다. 또한 제지슬러지소각재 대체 시 나타나는 단점인 수화열 및 흡수율의 증가로 인한 수축균열을 폴리프로필렌섬유 및 셀룰로오스섬유를 혼입하여 이에 대한 제어효과를 고찰하여 제지슬러지소각재의 시멘트 대체재로써의 활용가능성을 규명하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.333-338
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• 2000

The purpose of this study is to evaluate the compressive strength properties of municipal waste ash hardening using the unrefined fly-ash and paper sludge ash and to offer basic data to someone for recycling municipal waste ash. Unrefined fly-ash and paper sludge ash are used with admixture. MWA are tested that grading, specific gravity and pH value and observed microsructure of particle with SEM. The compressive strengths of MWA hardening which is mixed with regular ratio according to each admixture are measured. In the results of test, fly-ash is very effective for reducing content of cement by 50% in the recycling of MWA. But proper content mixed paper sludge ash is recommend by about 20% in binder.