• 한국재난정보학회 논문집
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• 제9권1호
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• pp.56-64
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• 2013

본 연구에서는 소입경 골재와 중온 기술을 사용한 저소음 포장의 현장 적용성 검토를 수행하였다. 배합설계 및 실내실험 수행결과, 소입경 골재를 사용하면 골재간의 맞물림 면적이 증가하여 비산저항성이 향상되는 것으로 나타났다. 고점도 아스팔트 바인더를 사용하는 저소음 아스팔트 포장은 선회다짐기를 통한 다짐온도 결정이 적합하였으며, 중온 첨가제 사용시 약 $15^{\circ}C$의 다짐온도 저감효과를 얻을 수 있었다. 시험 시공 후 현장투수시험과 소음측정을 하였으며 현장투수시험을 통해 저소음 포장이 충분한 공극을 확보하였음을 확인하였다. 소음측정결과 10mm 소입경 저소음 포장의 소음감소효과가 가장 뛰어난 것으로 나타났으며 공극률이 다소 작게 확보된 10mm 중온 소입경 저소음 포장도 13mm 저소음 포장에 비해 높은 소음감소효과가 나타나 소입경 골재의 사용이 저소음 포장의 소음감소에 효과적이었으며, 특히 저속에서의 소음감소효과가 뛰어났다.

• 한국건설순환자원학회논문집
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• 제11권4호
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• pp.542-551
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• 2023

본 논문에서는 바텀애시 골재에 천연 잔골재를 혼입한 다공성 콘크리트의 열적 특성을 분석하였다. 본 연구에서는 바텀애시 골재에 천연 잔골재를 사용하여 각 골재의 재료 특성을 파악 한 후, 다공성 콘크리트의 골재로 사용하였다. 물-바인더 비는 0.25으로 고정하여, 가압다짐을 0.5, 1.5 및 2.5 MPa 수준으로 지정하여 다공성 콘크리트 시편을 제작하였다. 단위질량, 총 공극률 및 열전도도 실험을 진행하고 분석을 수행하였다. 가압다짐 수준이 증가하고, 천연잔골재 혼입률이 증가하면 단위질량과 열전도도 값은 증가하였으며, 총 공극률 값은 감소하였다. 또한, 다공성 콘크리트의 단위질량과 총 공극률, 열전도도 상관관계 그래프를 제시하여 해외 실험 사례와 비교 분석하였다. 이후 실험 결과에 대한 회귀 분석을 진행하여 상관계수(R²) 값을 분석하였다.

• Structural Engineering and Mechanics
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• 제88권2호
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• pp.141-157
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• 2023

In the present paper, the effect of recycled aggregates on the rheological and mechanical properties of self-consolidating concrete is investigated experimentally and numerically. Hence, the specimen with two types of recycled aggregates, i.e., known and unknown resistance origins, are utilized for the studied specimens. The experiments in this study are designed using the Box-Behnken method, which is one of the response surface methods. Input variables in mixtures include silica fume in the range of 5-15% as a percentage substitute for cement weight and recycled coarse and fine aggregates in the range of 0-50% for both series of recycled materials as a substitute for natural materials. The studied responses are slump flow, V funnel, compressive strength, tensile strength, and durability. The results indicate that the increase in the amount of recycled aggregates reduces the rheological and mechanical properties of the mixtures, while silica fume effectively improves the mechanical properties. In addition, the results demonstrate that the fine recycled aggregates affect the total response of the concrete significantly. The results of tensile and compressive strengths indicate that the mixtures including 50% recycled materials with known resistance origin demonstrate better responses up to 8 and 10% compared to the materials with unknown resistance origins, respectively. Recycled materials with a specific resistance origin also show better results than recycled materials with an unknown resistance origin. Durability test results represent those concretes containing recycled coarse aggregates have lower strength compared to recycled fine aggregates. Also, a series of mathematical relationships for all the responses are presented using variance analysis to predict mixtures' rheological and mechanical properties.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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• pp.221-224
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• 2001

In this paper, the properties of concrete using recycled fine aggregate are anlyzed. Five different contents. 0%, 40%, 60%, 80% and 100% of recycled concrete were used for this study. At curing 280days, compressive strength, dry-shrinkage, static modulus of elasticity and poission's ratio have been tested according to replacement ratio of recycled fine aggregates.

• 콘크리트학회논문집
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• 제18권2호
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• pp.249-255
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• 2006

최근 건설현장에서 다양한 잔골재가 콘크리트에 사용되고 있으나, 이런 잔골재가 콘크리트에 미치는 영향에 대해 체계적으로 검토한 연구는 거의 없다. 따라서 본 연구에서는 최근 국내 건설현장에서 비교적 많이 사용되고 있는 잔골재 종류가 콘크리트의 품질에 미치는 영향을 검토할 목적으로 잔골재 종류가 콘크리트의 건조수축, 내구성, 수밀성에 미치는 영향을 분석하였다. 그 결과, 부순모래를 사용한 콘크리트는 바닷모래 및 강모래와 같은 천연모래를 사용한 콘크리트에 비해 건조수축이 증가되고, 내구성과 수밀성이 저하되며, 특히 입도 입형이 불량한 부순모래를 사용한 경우에는 더욱 콘크리트의 품질을 저하시키는 것으로 나타났다. 또한 입도 입형이 불량한 부순모래를 천연모래와 혼합하여 입도와 입형을 적절히 조절함으로써 콘크리트의 건조수축이 저감되고, 내구성과 수밀성이 향상되는 것으로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.463-466
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• 2005

This study examined the effects of comparatively widely used fine aggregates in the domestic construction fields on the quality of concrete through the analysis of the effects of such fine aggregates on the physical properties of fresh concrete and strength of hardened concrete. Results revealed that crushed sand degrades the fluidity and air entraining of concrete compared to natural aggregates like sea sand and river sand. Especially, the use of crushed sand exhibiting low grain shape and grade was seen to have larger adverse effect on the physical properties of concrete.

• International Journal of Concrete Structures and Materials
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• 제5권1호
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• pp.3-10
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• 2011

Theoretical models for prediction of the mechanical properties of cement mortar are developed based on the morphology and interactions of cement hydration products, capillary pores and microcracks. The models account for intermolecular interactions involving the nano-scale calcium silicate hydrate (C-S-H) constituents of hydration products, and consider the effects of capillary pores as well as the microcracks within the hydrated cement paste and at the interfacial transition zone (ITZ). Cement mortar was modeled as a three-phase material composed of hydrated cement paste, fine aggregates and ITZ. The Hashin's bound model was used to predict the elastic modulus of mortar as a three-phase composite. Theoretical evaluation of fracture toughness indicated that the frictional pullout of fine aggregates makes major contribution to the fracture energy of cement mortar. Linear fracture mechanics principles were used to model the tensile strength of mortar. The predictions of theoretical models compared reasonably with empirical values.

• 자원환경지질
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• 제32권1호
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• pp.13-18
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• 1999

The tailings stocked at two tailing piles in Sangdong aea have raised collapse hazards and various environmental problems. A trial for effective utilization of tailings as fine aggregates for polymer concrete has been performed along with mineralogical and physical characterization of tailings. The tailings from the Sangdong mine, mainly composed of quartz, orthoclase, amphiboles and muscovite, are alkaline and tailings at the new tailing pile are generally finer in grain size than those at the old tailing pile. In case of using New Tailings as fine aggregates, cement mortar with equivalent amounts of tailings and sands shows the highest compressive strength. Cement mortars containing tailings show lower values of compressive strength, splitting tensile strength and flexural strength than those not-containing tailings. Mixture of polymers such as SBR and EVA in cement mortars raises strengths of cement mortars effectively, which shows potential possiblity to utilize the tailings in Sangdong area as fine aggregates for polymer concretes.

• 한국세라믹학회지
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• 제51권5호
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• pp.492-497
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• 2014

Artificial fine aggregates (denoted AFA) were fabricated using spent bleaching clay (denoted SBC) generated from processed vegetable oil and stone sludge (denoted SS) produced from crushed aggregate manufacturing materials for use as functional construction materials. Each raw material was crushed to particle size finer than $150{\mu}m$, and fine spherical pellets of approximately 1 ~ 4 mm in diameter were prepared by a pelletizing process. The physical properties of the AFA were measured with different types of sintering equipment. A new type of vertical furnace that sinters fine aggregates in a fluidized bed at high temperatures was designed and tested. AFA sintered in a rotary kiln at $1125^{\circ}C$ showed a bulk density of $1.5g/cm^3$ and a water absorption of 16%. AFA sintered in the vertical furnace at $1125^{\circ}C$ showed a bulk density of $1.9g/cm^3$ and water absorption of 8.5%. The bulk density of the AFA sintered in the vertical furnace showed a bulk density 27% higher and water absorption 47% lower than those of AFA sintered in the rotary kiln.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.10-11
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• 2021

As concrete is used in many construction works, the use of aggregates is increasing. However, supply and demand of high-quality aggregates has become difficult recently, and although circular aggregates that recycle construction waste are used, the performance of concrete, such as liquidity and strength, are being reduced due to defective aggregates. As a result, quality tests such as sieve analysis test are conducted, but a lot of waste occurs such as time and manpower. To solve this problem, this study was conducted to measure the assembly rate of fine aggregate, which accounts for about 35% of the concrete volume, using Deep Learning.