• Journal of Energy Engineering
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• v.27 no.2
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• pp.55-60
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• 2018

In this study investigated the Controlled Low Strength Materials using coal ash and steel slag(KR slag) as the main material in the thermal power plant classified as waste resource. Bottom ash and KR slag are mixed at a ratio of 7: 3 to expand the use of industrial by-products through carbonate($CO_2$-fixation) reactions and inhibit the exudation of heavy metals. The results showed that the water content increased as the content of bottom ash increased. It was confirmed that as the powder content increased, the bleeding ratio decreased. Also, as the content of one kind of ordinary portland cement (OPC) decreased, activation of hydration reaction decreased and compressive strength decreased. However, when the mixed composition is appropriately adjusted, the compressive strength of 2.0 MPa required for the controlled low-strength material can be satisfied.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5C
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• pp.303-312
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• 2006

This study is to evaluate the mechanical characteristics of flowable backfill and offer a guide line of mixture proportion based on soil types for constructing underground power utilities. Flowable backfill is known as soil-cement slurry, void fill, and controlled low-strength material(CLSM). The benefits of CLSM are reduced equipment costs, faster construction, re-excavation in the future, and the ability to place materials in confined spaces, which are narrow parts or perimeters of underground power cables nearly impossible for compaction. The flowable slurry mixed with 17 soils and 6 accelerated mixtures in the laboratory were evaluated for flowability and unconfined compressive strength to meet the target values of this study.

• Journal of the Korean GEO-environmental Society
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• v.21 no.9
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• pp.25-32
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• 2020

The underground utilities installed under the ground is an important civil engineering structure, such as water supply and sewerage pipes, underground power lines, various communication lines, and city gas pipes. Such underground utilities can be exposed to risk due to external factors such as concentrated rainfall and vehicle load, and it is important to select and construct an appropriate backfill material. Currently, a method mainly used is to fill the soil around the underground utilities and compact it. But it is difficult to compact the lower part of the buried pipe and the compaction efficiency decreases, reducing the stability of the underground utilities and causing various damages. In addition, there are disadvantages such as a decrease in ground strength due to disturbance of the ground, a complicated construction process, and construction costs increase because the construction period becomes longer, and civil complaints due to traffic restrictions. One way to solve this problem is to use a liquid filler. The liquid filler has advantages such as self-leveling ability, self-compaction, fluidity, artificial strength control, and low strength that can be re-excavated for maintenance. In this study, uniaxial compression strength test and fluidity test were performed to characterize the mixed soil using marine clay, stabilizer, and in-situ soil as backfill material. A freezing-thawing test was performed to understand the strength characteristics of the liquid filler by freezing, and in order to examine the effect of the filling materials on the corrosion of the underground pipe, an electrical resistivity test and a pH test were performed.