• 한국문화재보존과학회:학술대회논문집
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• 2001.11a
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• pp.19-24
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• 2001

This study mainly reports preliminary results from site investigation of the Great Pyramids and Sphinx in Egypt and sampling works where conducted in the same limestone beds in Mokattam quarry in Cairo. Analyses of composition of samples showed similar result to those of limestone in Giza and thus such samples can be easily used for further experimental work without disturbing real monuments. Future work will be concentrated on the change of engineering properties of samples before and after artificial weathering and the change of digital image acquired from the colored surface of monuments.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.545-551
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• 2015

The aim of this research is suggesting application method of the wasted rock obtained from the limestone quarry of raw material for cement as a coarse aggregate for high strength concrete after crushing and sieving processes. The wasted rock has been normally wasted because of its low quality as a material for cement production. In this research, the concrete using this wasted limestone coarse aggregate was evaluated the constructability based on the performances of workability, air content, and compressive strength. From the experiment, a favorable performance was achieved with a limestone coarse aggregate for high strength concrete comparing to the high strength concrete using granite coarse aggregate.

• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.183-193
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• 1998

This study was designed, firstly, to determine the mineralogical and chemical characteristics of some rock aggregates, secondly, to offer interrelationships between those and mechanical properties, and thirdly, to evaluate their suitability for concrete aggregates. Mineralogical, chemical, physical and mechanical characteristics of the studied rock aggregates indicate that granite from BJ quarry and banded gneisses from KB. HI and SK quarry, and quartzite from the Hongcheon riverside are not proper to cement concrete aggregates because of quartz's potential possibility of alkali-silica reaction, and limestone in SY quarry is proper to asphalt concrete aggregates owing to dolomite causing alkali-carbonate reaction. Augen gneiss and diorite from KB and SA quarry, respectively, are to be not suitable for concrete aggregates because of biotite contents, but augen gneiss in HI quarry and gneisses in Hongcheon riverside are proper to concrete aggregates because of mineralogical and mechanical characteristics.

• Advances in concrete construction
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• v.7 no.2
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• pp.87-96
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• 2019

Self-compacting concretes (SCC) are highly fluid concrete which can flow without any vibration. Their composition requires a large quantity of fines to limit the risk of bleeding and segregation. The use of crushed sand rich in limestone fines could be an adequate solution for both economic and environmental reasons. This paper investigates the influence of quarry limestone fines from manufactured crushed sand on rheological, mechanical and durability properties of SCC. For this purpose, five mixtures of SCC with different limestone fines content as substitution of crushed sand (0, 5, 10, 15 and 20%) were prepared at constant water-to-cement ratio of 0.40 and $490kg/m^3$ of cement content. Fresh SCC mixtures were tested by slump flow test, V-funnel flow time test, L-box height ratio, segregation resistance and rheological test using a rheometer. Compressive and flexural strengths of SCC mixtures were evaluated at 28 days. Regarding durability properties, total porosity, capillary water absorption and chloride-ion migration were studied at 180 days. For the two test modes in fresh state, the results indicated compatibility between slump flow/yield stress (${\tau}_0$) and V-funnel flow time/plastic viscosity (${\mu}$). Increasing the substitution level of limestone fines in SCC mixtures, contributes to the decrease of the slump flow and the yield stress. All SCC mixtures investigated achieved adequate filling, adequate passing ability and exhibit no segregation. Moreover, the inclusion of limestone fines as crushed sand substitution reduces the capillary water absorption, chloride-ion migration and consequently enhances the durability performance.

• Tunnel and Underground Space
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• v.20 no.3
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• pp.183-193
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• 2010

The present paper highlights some important fragmentation issues experienced in the limestone quarry blast rounds. In light of these major issues, the paper outlines influence of a few important design parameters, which bear merit to alter the blast performance in order to duly resolve the issues in field scale blast rounds. A comprehensive field based program for evaluation of such blast rounds has also been suggested. The knowledge disseminated in the paper, backed up by sufficient images, is largely based on the experience of the authors, while designing, implementing and evaluating numerous field scale blast rounds in cement grade limestone quarries.

• Explosives and Blasting
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• v.31 no.2
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• pp.6-13
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• 2013

Recently, complaints or environmental problems caused by the noise and dust generated from crusher of the mine and quarry are emerging. Therefore mining facilities such as crushers and mills have been installed in an underground. In order to facilitate crusher equipments in the underground, excavation of large space is required and then the stability of the large space underground structure is an important issue. In this study, the blast experiments, which use a block of the limestone, are performed. Based on the blast experiments, the numerical model was prepared and simulated using dynamic fracture process analysis code(DFPA) with considering the rising time of applied borehole pressure and microscopic tensile strength variation. Comparing the non-dimensional crack length and no-dimensional tensile strength obtained from blast experiments and numerical analyses, the input parameters of DFPA code for predicting a radial tensile crack in limestone blasting were determined.

• Explosives and Blasting
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• v.25 no.2
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• pp.61-70
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• 2007

Korean large limestone mines started to employ bulk emulsion explosives to improve the productivity in early 2000s. As the application of the bulk emulsion explosives became common in the mid 2000s, the bulk emulsion application increases overall performance but it tends to decrease the moving and heaving because it lacks in gas volume and heat energy. Therefore, the chemical gassing technique was introduced to improve the blasting efficiency of the existing bulk emulsion explosives. The chemical gassing is a technique to replacing GMB(Glass Micro Balloon), which is used for a sensitizer, with gassing agent to chemically sensitize it. This paper introduces the case of successful application of chemical gassing in a Korean large limestone mine. We also compared and evaluated the blast and work efficiency between bulk emulsion GMB & gassing agent (chemical gassing). The results indicate that the replacement of GMB with gassing agent improved fragmentation in the upper part and toe of a bench as well as moving efficiency of the material.

• Explosives and Blasting
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• v.21 no.2
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• pp.31-42
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• 2003

본 연구는 일반건설현장에서와는 달리 천공경이 $97mm{\Phi}$이상이고 천공장이 21M이상인 상태에서 발파작업이 진행되고 있는 석회석 광산에서 기존의 발파공법과 Air tubes를 이용한 발파공법을 비교하여 기존의 발파로 인한 상부 대괴를 감소시키고 폭약의 사용량을 줄이면서 진동 및 폭음을 최소화하여 보다 경제적인 작업수행을 하기 위해 연구하였다. 한편 에어층(Air deck)을 형성으로 인한 전색장의 길이 감소를 보완하기 위해 라바플러그(Rubber Plug)를 사용하므로 비석의 위험을 최소화 시키고 가스압이 암전체에 충분히 전달할 수 있도록 장치를 만들어 실험하였다. 그 결과 일반발파와 Air tubes를 이용한 발파방법을 비교하여 볼 때 Air tubes를 이용한 발파방법이 폭약을 약 15~30% 절감 할 수 있었으며, 또한 진동은 최대 50%정도의 감소와 폭음에서는 2~5dB 정도로 감소되었다.

• Advances in concrete construction
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• v.9 no.2
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• pp.217-225
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• 2020

The recovery of waste proves a solution with two impacts: the environmental impact by the reduction of pollution and the gain of the occupied space by this waste, and the economic impact by the use of these lasts in the building and in the area of public works. The present research consists in recovering a waste marble (thrown powder exposed to the different meteorological phenomena) generated by the quarry marble of Fil-fila, located at the east side of Skikda in the north-east of Algeria, and add it, as sand in the composition of sand concrete. To carry out this research, we analyzed the evolution brought by the substitution of ordinary sand by marble waste sand, with 25%, 50%, 75% and 100% on the properties in the fresh state (density, workability and air content) and in the cured state (compressive strength, tensile strength, surface hardness and sound velocity). For durability we tested water absorption by immersion and chloride penetration. The results obtained are compared with control samples of 0% of substitution rate. In order to have a good filling of the voids in the granular skeleton; we added a quantity of limestone recycled fines from the quarries and for a good workability a super-plasticizing additive. The results showed that the partial substitution modified both the fresh and the hardened characteristics of the tested concretes, the durability parameters also improved.

• Explosives and Blasting
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• v.28 no.1
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• pp.19-26
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• 2010

The paper presents a case study of a limestone quarry of the Philippines, where major problems in terms of improper fragmentation, poor wall control, and poor heave of the muck pile were witnessed. The paper highlights the significant role of switching over from diagonal firing pattern to V-type firing pattern, and also of making suitable adjustments in the stemming column length for improved confinement and gas retention. The study revealed that by making aforesaid design modifications in the blast round, marked improvement in blasting results was registered. Looking at the results, it was further contemplated to expand the mesh area in the subsequent blast rounds. The mesh area was incremented from the existing $8.96m^2$ to $12m^2$. The results were meticulously registered in the field, and clearly depicted definite improvements in the blast results in terms of increased P.F., reduced boulder count, reduced FEL cycle time, reduced dozing hours and improved heave.