• Magazine of RCR
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• v.13 no.3
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• pp.10-14
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• 2018

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.77-85
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• 2010

Unconfined compressive strength tests were performed to evaluate curing characteristics of controlled low strength material(CLSM) made with coal ashes. It is found that unconfined compressive strength normalized by curing times, increases as decreasing the water contents of CLSM particularly during first three days. Dynamic cone penetrometer tests were also carried out to evaluate cost-effective CLSM lump strength characteristics with time. It takes around 10 days to reach target strength, 500kPa (penetration rate, 20mm/blow). Curing rate significantly decreases after 10 days elapsed regardless of CLSM formulation.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.159-160
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• 2017

Recently, researches on controlled low strength materials using coal ashes have been actively conducted in Korea. Controlled Low Strength Material by using a large amount of Coal Ashes, which is a by-product of the industry, will solve the environmental problems caused by coal ash as well as economic formulation. In this paper, the compressive strength and flow of the CLSM binder were investigated in order to select the optimum mixing ratio.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1295-1302
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• 2006

Controlled low-strength material(CLSM) which is easily excavated and also known as flowable material, is commonly used as a backfill in utility trenches and other applications. In this study, a rapid-setting flowable material a kind of CLSM made with a field soil were evaluated by an experimental study. The properties ordinarily desired from the mix are: (a) flow under gravity; (b) hardening for early workability(after 4 hours)and cover; and (c) ultimate strength low enough to allow ready excavation. Fluidity of fresh material is evaluated using a simple spread test. Hardening is measured by a mortar penetrometer, and these values are correlated with unconfined compressive strength. It is desirable to keep the ultimate strength to less than $5.6kg/cm^2$ somewhat less target strength is selected for the 28-day value.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.32-37
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• 2010

Recently, the land area for many people has been limited because of industrialization and modernization in Korea. The large-scale constructions like the reclamation development projects have been progressed to resolve this problem mentioned above. Therefore, as many of the usefulconstruction materials as possible are needed to perform the large-scale construction projects. Many studies for the utilization of pond ash which has a similar characteristic of sand have been conducted and there has been often occurred many structural problems on roadbed in winter. Therefore, the characteristics of the freezing and thawing for Controlled Low-Strength Material (CLSM) using pond ash were analyzed and evaluated by unconfined compressive strength test in this study. As a result of this study, it was confirmed that new CLSM using pond ash with cement (8.2% by weight)was able to stand for the freezing and thawing behavior.

• Resources Recycling
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• v.26 no.3
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• pp.32-38
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• 2017

For the massive recycling of mine tailings, which are an inorganic by-product of mining process, in the field of civil engineering, pretreatments to extract heavy metals are required. This study focuses on the use of pre-treated tailings as substitute fillers for controlled low-strength material (CLSM). As a comparative study, untreated tailing, microwave-treated tailing and magnetic separated with microwaved tailing were used in this study. Cement contents amounting to 10%, 20% and 30% by the weight of the tailings were designed. Both compressive strength and flowability for all types of mixture were satisfied with the requirements of the American Concrete Institute (ACI) Committee 229, i.e., 0.3-8.3 MPa of compressive strength and longer than 200 mm flowability. Furthermore, all mixtures showed settlements less than 1% by volume of the mix.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.142-147
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• 2000

Durability characteristics of controlled low strength material(flowable fill) with high volume fly ash content was examined. The mix proportions used for flowable fill are selected to obtain low-strength material in the 10 to 15kgf/㎥ range. The optimized flowable fill was consisted of 60kgf/㎥ cement content, 280kgf/㎥ fly ash content, 1400kgf/㎥sand content, and 320kgf/㎥water content. Subsequently, durability tests including permeability warm water immersion, repeated wetting & drying, freezing & thawing for high volume fly ash-flowable fill are conducted The test results indicated that flowable fill has has acceptable durability characteristics.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.11-18
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• 2009

When underground pipe is installed, backfill materials need proper compaction. But in case of circular underground pipe, compaction of backfill material is difficult and compaction efficiency is poor at beloe the pipe. It caused the stability of underground pipe is reduced and various damages occurred. One of the solutions to solve this problem for underground pipe is to use controlled low strength material (CLSM). CLSM is made by concept of low strength concrete, which is applied to geotechnical engineering field. The representative characteristics of CLSM are self-leveling, self-compacting and flowability. In addition, its strength can be controlled and its construction method is simple. The behavior of underground pipe was investigated by finite element analysis for various backfill materials under same condition. As a result, in case of using the CLSM as backfill material, surface settlement and displacement of pipe are reduced comparing with those in case of using field soil or sand.

• Computers and Concrete
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• v.30 no.6
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• pp.393-407
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• 2022

Due to the enormous cement content, pozzolanic materials, and the use of different aggregates, sustainable controlled low-strength material (CLSM) has a higher material cost than conventional concrete and sustainable construction issues. However, by selecting appropriate materials and formulations, as well as cement and aggregate content, whitethorn costs can be reduced while having a positive environmental impact. This research explores the desire to optimize plastic properties and 28-day unconfined compressive strength (UCS) of CLSM containing powder content from unprocessed-fly ash (u-FA) and recycled fine aggregate (RFA). The mixtures' input parameters consist of water-to-cementitious material ratio (W/CM), fly ash-to-cementitious materials (FA/CM), and paste volume percentage (PV%), while flowability, bleeding, segregation index, and 28-day UCS were the desired responses. The central composite design (CCD) notion was used to produce twenty CLSM mixes and was experimentally validated using MATLAB by an Artificial Neural Network (ANN). Variance analysis (ANOVA) was used for the determination of statistical models. Results revealed that the plastic properties of CLSM improve with the FA/CM rise when the strength declines for 28 days-with an increase in FA/CM, the diameter of the flowability and bleeding decreased. Meanwhile, the u-FA's rise strengthens the CLSM's segregation resistance and raises its strength over 28 days. Using calcareous powder as a substitute for cement has a detrimental effect on bleeding, and 28-day UCS increases segregation resistance. The response surface method (RSM) can establish high correlations between responses and the constituent materials of sustainable CLSM, and the optimal values of variables can be measured to achieve the desired response properties.

• Journal of the Korea Concrete Institute
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• v.12 no.1
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• pp.113-125
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• 2000

The purpose of this study was to examine the durability characteristics of controlled low strength material(flowable fill) with high volume fly ash content. Flowable fill refer to self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. The two primary advantages of flowable fill over traditional methods are its ease of placement and the elimination of settlement. Therefore, in difficult compaction areas or areas where settlement is a concern, flowable fill should be considered. The fly ash used in this study met the requirements of KS L 5405 and ASTM C 618 for Class F material. The mix proportions used for flowable fill are selected to obtain low-strength materials in the 10 to 15kgf/$\textrm{cm}^2$ range. The optimized flowable fill was consisted of 60kg f/$\textrm{m}^3$ cement content, 280kgf/$\textrm{m}^3$ fly ash content, 1400kgf/$\textrm{m}^3$ sand content, and 320kgf/$\textrm{m}^3$ water content. Subsequently, durability tests including permeability, warm water immersion, repeated wetting & drying, freezing & thawing for high volume fly ash-flowable fill are conducted. The results indicated that flowable fill has acceptable durability characteristics.