• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.294-300
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• 2001

The effectiveness of bottom ash on the mechanical and physical properties of Controlled Low-Strength Material(CLSM) is investigated in this study, CLSM is defined by the ACI Committee 229 as a cementitious material that is in a flowable state at the time of placement and having a specified compressive strength of 83 kgf/$\textrm{cm}^2$ or less at the age of 28 days. This study was undertaken on the use of bottom ash as a fine aggregate in CLSM. Four different levels of bottom ash with fly ash contents, 25%, 50 %, 75%, 100%, are investigated. Laboratory test results conclude that inclusion of bottom ash increases the demand for mixing water in obtaining the required flow. However, the sand was reduced because it was adjusted to maintain a constant total volume. Miかe proportions were developed for producing CLSM at three 28-day strength levels: removal with tools (less than 7 kgf/$\textrm{cm}^2$), mechanical means (less than 20 kgf/$\textrm{cm}^2$), and power equipment (less than 83 kgf/cm\`). The physical and mechanical properties supports the concept that by-product bottom ash can be successfully used in CLSM.

• 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.

• Resources Recycling
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• v.29 no.1
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• pp.43-52
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• 2020

The objectives of this study were to identify the optimal mix of foam concrete with the low-strength and high-flow for the repairing ground subsidence situation emergently by utilizing a large amount of industrial by-products and evaluate the possibility by applying it to the site. The factors of the experiment were the mixing ratio of mixing water and a foaming agent and the mixing ratio of foam over paste volume. The optimal mix identified by the experiment was applied to the field and basic properties were evaluated. The results of the experiment showed that the optimal mixing ratio of mixing water and the foaming agent was 10%. Moreover, when the mixing ratio of pre-foam over paste volume was 170%, it satisfied the target. However, to ensure stable quality when applying to the field, the foam mixing ratio was set 140% for the field application. The field application test of foam concrete with the low-strength and high-flow using an eco-friendly binder satisfied all target performances. Therefore, the possibility of using it as a mixture and construction method for a ground repair system is confirmed. However, there was a quality deviation between the upper part and the lower part due to the separation between foam and paste. Consequently, further studies are needed to improve it.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.109-114
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• 2001

In this study, the physical and dynamic characteristics of Bottom-ash produced at steam power plants were compared and considered. The comparative objects were Bottom-ash in which a lot of powder contained and that in which less than that relatively contained. The difference in quantity of powder showed different effect on the character of flow. This study was undertaken on the use of Bottom-ash as a fine aggregate, and showed the durability and the character of strength according to each rate.

• Resources Recycling
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• v.29 no.1
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• pp.53-61
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• 2020

This study aimed to develop a foam concrete material for a ground repair system that has low strength and low fluidity by using an eco-friendly binder, which substitutes industrial by-products for more than 90% of cement. Basic properties were evaluated after substituting a small amount of calcium sulfo aluminate (CSA) for the binder to improve the sinking depth rate and volume change, commonly found when it had a large amount of industrial by-products. The substitution rates of CSA for the eco-friendly binder used for the foam concrete were 2.5, 5, and 10%. Fresh properties, hardened properties, pore structure, and hydrates were analyzed. Experimental results showed that using only 2.5% of CSA could improve the deep sinking depth which occurred when using an eco-friendly binder. As a result, the weight difference between the upper, middle, and lower parts of cast specimens was improved even after being hardened. The addition of CSA also contributed to the formation of small, uniformly sized closed pores and improved initial strength. However, when the proportion of CSA increased, the long-term strength decreased. However, it satisfied the target strength when 5% or less of CSA was used. The results of this study revealed that it was possible to manufacture foam concrete with low strength and high fluidity for repairing ground satisfying target qualities by adding 2.5% of CSA to the eco-friendly binder containing a large amount of industrial by-products.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.142-146
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• 2001

This research was undertaken on the use of bottom ash as a fine aggregate in Controlled. Low-strength Material(CLSM). The mixtures contained constant fly ash. And four different level of bottom ash with fly ash contents, 25%, 50%, 75%, 100% are investigated. Mixture proportions were developed for producing CLSM at three 28-day strength levels: removal with tools (less than $7kgf/cm^{2}$), removal by mechanical means (less than $200kgf/cm^{2}$), and removal with power equipment (less than $83kgf/cm^{2}$). To obtain these strengths, cement contents of 30, 60, and $120kg/cm^{3}$ were utilized. The compressive strength properties support the concept that by-product bottom ash can be successfully used in CLSM.

• 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.