• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.135-141
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• 1999

This study is an experimental study to investigate the possibility of the utilization of paper ash as the cover, liner in waste disposal landfill and other construction materials. The sample used in these tests was obtained from Daehan paper mill. A series of tests were peformed to evaluate basic properties, compaction, permeability, compressive strength, consolidation, leaching, and CBR of paper ash. In order to investigate the soil engineering properties of paper ash, the test results were compared with those obtained of fly ash. The results of unconfined compression tests show that paper ash had a larger strength than the fly ash. Also, the maximum dry unit weight of paper ash was approximately 59～76.9% less than that of the fly ash. It was found from the results of leaching test that paper ash is classified as non-detrimental general wastes according to the waste management law.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.827-830
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• 2008

In this study, large triaxia mpression tests of sand-gravel soils were carry out to clarify the influence of fines on shear strength characteries. Two soil specimens with/without fines that is used for construction material of dam were prepared. One was reproduced with wide range of grain size and the other was removed fines below 2mm from the one. The compaction tests proposed by our center were performed to obtain relative density of the specimens, and then each specimen was adjusted two dry density. The large triaxial compression tests were carry out under CD condition. Based on the results, the sand-gravel soils with low fines content has no effect on shear strength characteries.

• Structural Engineering and Mechanics
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• v.84 no.4
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• pp.465-477
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• 2022

The formation of biopolymer-soil matrices mainly depends on biopolymer type and concentration, soil type, pore fluid and phase transfer to influence its strengthening efficiency. In this study, the physical and mechanical properties of sodium alginate (SA) treated kaolinite are investigated through compaction test, thread rolling teat, fall cone test and unconfined compression test with considering biopolymer concentration, curing time, initial water content, mixing method. The results show that the liquid limit slightly decreases from 69.9% to 68.3% at 0.2% SA and then gradually increases to 98.3% at 5% SA. At hydrated condition, the unconfined compressive strength (UCS) of SA treated clay at 0.5%, 1%, 2% and 3% concentrations is 2.57, 4.5, 7.1 and 5.48 times of untreated clay (15.7 kPa) at the same initial water content. In addition, the optimum biopolymer concentration, curing time, mixing method and initial water content can be regarded as 2%, 28 days, room temperature water-dry mixing (RD), 50%-55% to achieve the maximum unconfined compressive strength, which corresponds to the UCS increment of 593%, compared to the maximum UCS of untreated clay (780 kPa).

• Current Research on Agriculture and Life Sciences
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• v.18
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• pp.61-69
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• 2000

This study was conducted to investigate most effective the optimum lime content for lime-clay modification. To achieve the aim, characteristics of compaction and compressive strength were tested by adding of 0, 5, 10, 15 and 20% lime (Hydrated lime) of dry weight of the clay. Distilled water was added 10, 15, 20 and 25% of dry weight of lime-clay mixture. In this test, the compressive strength of the specimens was measured according to the following curing period : 7, 21, 28, 35 and 49 days. The results are as follows. (1) As lime additive increased, the optimum moisture content of lime-clay mixture was increased and the maximum dry density was decreased. (2) The soil mixture of 20% of the moisture content and 10% of lime additive was shown the maximum compressive strength. (3) As curing period longer, the compressive strength was increased but after 21 curing days, the increasing rate of compressive strength was low as compared with earlier its value. (4) In the range of 20% of the moisture content, compressive strength of mixture of 10% lime additive increased twice compared with that of mixture of 0% lime additive. (5) All of the lime-clay are possible to use for an sub-base material and 20% of moisture content of lime-clay mixture is possible to use for a base material.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.703-721
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• 2017

The experimental study of the behavior of dry medium and loose sandy soil under the action of a single impulsive load is carried out. Different falling masses from different heights were conducted using the falling weight deflectometer (FWD) to provide the single pulse energy. The responses of soils were evaluated at different locations (vertically below the impact plate and horizontally away from it). These responses include; displacements, velocities, and accelerations that are developed due to the impact acting at top and different depth ratios within the soil using the falling weight deflectometer (FWD) and accelerometers (ARH-500A Waterproof, and Low capacity Acceleration Transducer) that are embedded in the soil and then recorded using the multi-recorder TMR-200. The behavior of medium and loose sandy soil was evaluated with different parameters, these are; footing embedment, depth ratios (D/B), diameter of the impact plate (B), and the applied energy. It was found that increasing footing embedment depth results in: amplitude of the force-time history increases by about 10-30%. due to increase in the degree of confinement with the increasing in the embedment, the displacement response of the soil will decrease by about 25-35% for loose sand, 35-40% for medium sand due to increase in the overburden pressure when the embedment depth increased. For surface foundation, the foundation is free to oscillate in vertical, horizontal and rocking modes. But, when embedding a footing, the surrounding soil restricts oscillation due to confinement which leads to increasing the natural frequency, moreover, soil density increases with depth because of compaction, that is, tendency to behave as a solid medium.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.177-186
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• 1992

In this study, the proper mixing ratio of fly ash to bottom ash is evaluated and bearing capacity of this mixed ash is examined for use of highway embankment and subgrade materials in large quantities. Independently of the mixing ratio of fly ash to bottom ash or the method of compaction test, maximum dry density ${\gamma}_{dmax}$ and CBR value of anthracite mixed coal ash is greater than that of bituminous mixed coal ash. The mixed ashes to contain more fly ash than that of which the ratio of fly ash to bottom ash is 8 : 2, are slaked readily when the water contents of compaction are greater than optimum moisture content O.M.C. The proper mixing ratios of fly ash to bottom ash are about 5 : 5 to 6 : 4. Coal ashes mixed with these ratios exhibit proper physical and geotechnical properties for use of highway embankment and subgrade materials, and enable coal ashes to be used in large quantities.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.366-374
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• 2017

This study investigates enzyme stabilization in clay-rock bricks through mechanical tests and image processing. Appropriate soil mixtures were designed using clay/crushed rock with ratios of 70/30, 60/40, 50/50, 40/60, and 30/70 by weight to verify the strength of the enzyme brick and soil compaction. The maximum compressive and flexural strengths in the 60/40 ratio mixture were found to be 5MPa and 1.25MPa, respectively; however, the maximum dry unit weight of $2.073g/cm^3$ was found in the 50/50 clay/gravel ratio mixture. Generally, the strength of the enzyme brick was improved by 27%. The paper concludes that in order to achieve optimal strength, soils should be mixed with the 60/40 clay/gravel ratio, which provides an adequate strength, while 50/50 ratio should be used for achieving more compaction. The SEM-EDX observation and Matlab image processing verified how the bond structure appeared after enzyme stabilization. It was found that enzymes created bond with the clay soil and the crushed rock for rendering strength and stability.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.987-992
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• 2009

Continuous Compaction Control is a new cutting edge technique in United States, Japan and European construction market that uses an instrumented compactor to measure soil stiffness in real time usually with vehicle tracking system such as Global Navigation Satellite System (GNSS). In this study, soil stiffness was evaluated by adapting Fourier transforming technique with acceleration data obtained from accelerometers used as a continuous compaction control instrument. The soil stiffness obtained by accelerometers gave analogous results with reference results such as dry density, elastic modulus obtained from Geogauge and Light falling deflectometer.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.67-73
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• 2006

In this study, basic physical tests and mechanical tests of crushed rock were performed in order to investigate the field application of crushed rock as substitute materials of sand that is commonly being used as foundation and backfill materials of sewer conduit. Particle-size distribution curve of crushed rock is similar to sand and also it is well-graded soil than common sand. Maximum dry unit weight in proctor compaction test for crushed rock is higher than the values of common sand. So we can estimate that the crushed rock has advantages in workability than sand for the backfill compaction after construction of sewer conduit. When we investigate the results of direct shear test and triaxial compression test on the crushed rock, it has a similar value of shear strength parameters to sand at the same stress state and as time goes by, it tends to increase the unconfined compression strength. But, because the strength reaches at the constant value after 6~7 days, we expect that it can absorb the lateral strain of flexible conduit well. All the above experimental results just proves that crushed rock can substitute for sand as backfill materials and foundation of sewer conduit.

• Journal of Soil and Groundwater Environment
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• v.21 no.2
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• pp.1-7
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• 2016

Ferrous slag is a by-product from steel making process and waste concrete is generated from construction activities. Large part of ferrous slag and waste concrete are recycled as construction materials. However, Ca²⁺ leaching out of ferrous slag and waste concrete in the water-contacting environment can cause a strength change. Strength can be reduced due to the dissolution of solid form of CaO which is one of the main contents of ferrous slag and waste concrete. On the other hand, strength can be enhanced due to the pozzolanic reaction of cementitious components with water. In this study, steelmaking slag, blast furnace slag, and waste concrete were aged by exposure to raining events, and the change of their compaction and shear strength characteristics was investigated. Optimum moisture content of all materials used in this study increased with aging period while maximum dry unit weight slightly decreased, implying that the relative contents of fine particles increased as the CaO solid particles were dissolved. Internal friction angle and shear strength of recycled materials also increased with aging period, indicating that the materials became denser by the decrease of void ratio attributed to the fine particles generated during the weathering process and the development of cementitious compounds increasing the bonding and interlocking forces between the particles. The results of this study demonstrated that mechanical strength of recycled materials used as construction materials has little chance to be deteriorated during their service life.