• Magazine of the Korea Concrete Institute
• /
• 제10권5호
• /
• pp.167-176
• /
• 1998

골재의수요는 매년 크게 증가하고 있으나 천연골재는 점차 고갈되어 가고 있다. 따라서 기존석산들에서 발생되는 폐석자원을 쇄석골재로 활용하면 일거양득의 효과가 있다. 본 연구는 국내에서 가장 대규모 석산단지인 포천 및 익산지역 기존석산에서 발생되는 석산폐석에 대한 물리적, 화학적 및 광물학적 시험.분석을 실시하여, 쇄석골재로서 석산폐석의 특성규명과 활용가능성을 평가하였다. 연구결과, 포천과 익산지역에서 발생되는 석산폐석을 쇄석골재로 활용할 수 있을 것으로 판단되었으며, 폐석자원을 쇄석골재로 활용함으로써 골재의 수요에 보충하고, 산림 및 자연경관의 훼손과 환경오염을 야기할 수 있는 석산골재 신규개발의 억제에도 효과가 기대된다.

• Magazine of the Korea Concrete Institute
• /
• 제7권1호
• /
• pp.136-144
• /
• 1995

근래 양질의 하천골재가 거의 고갈상태에 직면함에 따라 쇄석골재의 사용이 보편화되고 있는 우리나라의 실정에 비추어 볼 때 골재의 화학반응에 대한 연구의 필요성이 점차 증대되고 있다. 본 연구에서는 우리나라에서 실제 쇄석골재를 생산하는 238곳 중 63곳의 시료골재를 채취하여 화학적, 광물학적, 모르터 바 분석실험을 실시하여 골재의 화학반응성을 규명하였다. 분석시험 결과 대부분의 시료골재가 화학반응성을 나타내지 않았으나 광물학적 분석에서 유해광물로 알려진 성분들이 여러 시료골재에 포함되어 있었다. 따라서 해사의 사용 등 점차 화학반응 환경이 공존하게 되면 골재의 화학반응이 일어날 가능성이 커지므로 계속적이고 심도있는 연구가 요구되고 있다.

• Magazine of the Korea Concrete Institute
• /
• 제9권3호
• /
• pp.119-126
• /
• 1997

Recently, duc to highly increased consumption of' ngg~.egatc>s f o ~ . construction. studies have focused on the effective utilization of rock wastes abandoned so far. This study was designed, firstly, to determine t,hc petrological, g'ochemical and mechanical cha~,acte~istics of' crushed limestone aggregates in thc Samhwa district for suitable construction aggregates and, secondly, to offer basic data for cff'ective utilization of low grade limestones. Results of' the petrographic st,udy indicates that the crushed limestone aggregates in the Samhwa district can bo separate4 into two groups, namely f'inc-grained and cowlxcgrained limestones. Dominantly distributed fine-grained limestone containing some dolomite has higher Mgo and $SiO_2$ contents compared to the coarse-graincd limestonr. It, can be classified as medium strength rock by the physical and mcxhanical pi.opertics. I3ased on the size of' mineral grains and chemical compositions, it is suggested that the crushed limestone aggregates in t,his study area would bctkr be u s ~ i for asphalt concr.ctt., road pavement, or railroad ballast materials than for cement concrete.

• Journal of the Korean Recycled Construction Resources Institute
• /
• 제3권2호
• /
• pp.132-139
• /
• 2015

In this study, the different unit cement content by the ratio of water absorption and water-cement ratio are applied to examine the properties of the concrete used the aggregate recycled by the crushing treatment. According to the experimental results, in the mix of low strength and high water-cement ratio, both of the compressive strength is almost equal in the concrete using the recycled aggregate by the crushing treatment and the concrete using broken stones. It means that the recycled aggregate has the low effect of the amount of bonded mortar. But, in the mix of high strength and low water-cement ratio, the concrete using the recycled aggregate by the crushing treatment has 40% less of the compressive strength than that using broken stones by the effect of the amount of bonded mortar. On the other hand, after 8 weeks, the dry shrinkage of the recycled aggregate with 7% of the ratio of water absorption doubles that of the broken stones with 1% ($-350{\times}10^{-6}$), in other words $-700{\times}10^{-6}$. Thus, the dry shrinkage should be prior to any other conditions in recycling waste concrete for the aggregate for concrete. When the recycled aggregate with 3% of the ratio of water absorption is used, the compressive strength of the rich mix concrete ($450kg/m^3$ of the unit cement content) is equivalent to that of the concrete using broken stones, while in using the recycled aggregate with 7% of the ratio of water absorption, the rich mix concrete has 7% lower compressive strength than the concrete using broken stones. But, the compressive strength of the ordinary mix concrete ($350kg/m^3$ of the unit cement content) is far lower than that using broken stones.

• Korean Journal of Agricultural Science
• /
• 제32권1호
• /
• pp.19-27
• /
• 2005

This study was performed to evaluate the physical and mechanical properties of polymer concrete using unsaturated polyester resin, initiator, heavy calcium carbonate, crushed gravel, recycled coarse aggregate, silica sand and recycled fine aggregate. The unit weight, compressive strength, flexural strength and dynamic modulus of elasticity were decreased with increasing the content of recycled aggregate. The unit weight, compressive strength, flexural strength and dynamic modulus of elasticity were showed in $2,127{\sim}2,239kg/m^3$, 80.5~88.3MPa, 19.2~21.5MPa and $254{\times}10^2{\sim}288{\times}10^2MPa$ at the curing age 7 days, respectively. Therefore, these recycled aggregate can be used for polymer concrete.

• Magazine of the Korea Concrete Institute
• /
• 제6권2호
• /
• pp.108-117
• /
• 1994

This study was performed to investigate the Alkali-Silica Reaction(ASR) of crushed stones using chemical analysis, polarization microscope, XRD, chemical method(KS F 2545, ASTM C 289), mortar-bar method( KS F 2546, ASTM C 227) and Scanning Electron Microscope (SEM ) and Energy Dispersive X-ray Analysis(EDXA) of reaction products by ASK in the mortar bars and to investigate the influence on alkali content and kind of added alkali to the ASR. Test results show that one kind of domestic crushed stone is estimated as deleterious by ASTM chemical method and mortar bar method, and reaction product is proved as alkali silicate gel by EDXA.

• Magazine of the Korea Concrete Institute
• /
• 제3권2호
• /
• pp.11-16
• /
• 1991

• Cement
• /
• 통권63호
• /
• pp.24-34
• /
• 1976

• 레미콘
• /
• 4호통권43호
• /
• pp.49-59
• /
• 1995

• Journal of the Korean Geotechnical Society
• /
• 제38권4호
• /
• pp.33-45
• /
• 2022

A series of model tests were performed in this study to demonstrate the clogging mechanism created during the installation of a compaction pile to improve soft ground. The application of an air-jet to extrude sand or aggregates from a casing during the installation of a compaction pile imposes a remarkably high-pressure difference between the composite soil layers of clay and sand (or aggregates), resulting in severe clogging. Therefore, a one-dimensional testing system was developed to simulate composite soil layers consisting of clay and sand (or aggregates) and to apply a high-pressure differential at both boundaries, thus replicating the extrusion process used in compaction pile installation. Herein, the performance of two construction materials for compaction piles of crushed stone and grading-controlled aggregates was compared. A series of one-dimensional model tests were performed under multiple pressure settings, with clogging depth and permeability measured in each case. Results indicate that, blinding clogging mechanisms and blocking defined by previous studies were observed for crushed stone, and a new mechanism of "infiltration" was revealed and defined. Whereas, the controlled aggregates performed excellently against clogging because only blinding was observed.