The study is about the use of porous light bottom ash which is obtained from the dry-process of a thermoelectric power plant, as a lightweight aggregate for concrete.
The study evaluated the physicochemical characteristics of dry-processed bottom ash and provided the optimum processing conditions for bottom ash to be used as a aggregate. Additionally, the study conducted comparative evaluation between foreign and domestic artificial lightweight aggregates with the purpose of comprehending their performances, and concrete application studies. The characteristics of the concrete according to the various mixtures were examined in order to suggest a commercialization plan for dry-processed bottom ash as a structural lightweight aggregate concrete and as a concrete secondary-product lightweight aggregate.
The particle shapes and the surface texture of the dry-production bottom ash were improved by the physical method, in order to use it as a lightweight aggregate for concrete. The physicochemical characteristics before and after processing were examined, and its potential as a structural lightweight aggregate was examined by manufacturing the concrete following various mixing conditions and by conducting performance evaluations.

Accordingly, the range of the study was the physicochemical characteristics of the dry-processed bottom ash before and after the surface treat processing for its characteristics as a lightweight aggregate, and also on the particle shapes before and after processing. To examine its characteristics as a lightweight aggregate for concrete, the experiment was set to conduct flow, air amount, compression strength, tensile strength, unit volume weight, and elastic modulus as well as the durability items of freeze-thaw resistance and the chloride ion penetration test.
The configuration of this dissertation consists of six chapters, which are introduction, document studies, characteristics of bottom ash emitted during dry-production, characteristics of dry-production bottom ash as a lightweight aggregate following processing conditions, characteristics of concrete which uses a bottom ash lightweight aggregate, and conclusion.

The particle shapes and surface texture of the dry-processed bottom ash were treated in order to use it as a lightweight aggregate, and the examination of its physicochemical characteristics before and after processing performed and thus it was found that density and unit volume weight were increased rather than before processing. Additionally, the absorption rate was decreased with the treatment. Hence it was confirmed the usability of irregular shaped bottom ash as an aggregate by spheronization.
From the chemical analysis of dry-processed bottom ash, it was found that the unburned carbon was below 1% and the water and chloride content was below the standard threshold. According to the heavy metal leaching test, the amount of leached out hazardous substances, with the purpose of user safety, was so little that it was safe.
Furthermore, from the exam of the concrete mixture, the bottom ash lightweight aggregate before and after processing revealed that processing bottom ash using spallation and tritaration as the most advantageous from the aspect of the concrete solidity.

The concrete test conducted with various water cement ratios, unit quantities, and fine aggregate percentages showed that solidity and elastic modulus improved with the increase in unit weight. The freeze-thaw test for evaluating durability showed that it was necessary to considerable air content.
According to the concrete tests with differently mix designed for each artificial lightweight aggregate from abroad and domestic, it revealed that they were relatively unfavorable in aspect of flow and solidity, but advantageous in aspect of decreased unit volume weight. However, when the bottom ash lightweight aggregate was applied to concrete, its maximum compressed strength was over 40㎫, and its elastic modulus also indicated similar results, proving that it would not be a problem in actual application.
Also the bottom ash lightweight aggregate possesses the characteristics of general lightweight aggregates, including insulation, sound absorption, and heat, as a porous material, so it will be applicable to concrete or secondary concrete products that require such characteristics.