Electric arc furnace oxidizing slag, a by-product of the steel industry that can replace natural aggregates, not only lessens the environmental load, but also has positive economic impact. It was confirmed that the compressive strength of concrete with electric arc furnace oxidizing slag aggregates is 20% higher than that of concrete with natural aggregates for the same concrete mix, and it is possible to reduce the volume of cement at least 10% in attaining the same levels of compressive strength of concrete. Furthermore, its superior compression resistance leads to a higher deformation-resistance capacity compared to natural aggregates in terms of structural perspective. Determined in this study was the characteristic of compressive stress distribution of concrete with electric arc furnace oxidizing slag aggregates providing the basis of flexural performance evaluation of structural members. In addition, the effect of the characteristic on the bending behavior and performance of reinforced concrete was theoretically investigated based on experimental results.
This dissertation consist of six chapters, and each chapter includes the following content.

Chapter Ⅰ: Introduction

Chapter Ⅱ: Flexural theory considering compressive stress distribution characteristics of concrete

Chapter Ⅲ: Research trends of electric arc furnace oxidizing slag aggregates

Chapter Ⅳ: Compressive stress distribution characteristics of concrete with electric arc furnace oxidizing slag aggregates

Chapter Ⅴ: Flexural behavior prediction of reinforced concrete beams with electric arc furnace oxidizing slag aggregates

Chapter Ⅵ: Conclusions

The conclusions of this study can be summarized as follows.

1) Specimens with electric arc furnace oxidizing slag aggregates exhibited a high elastic modulus before peak stress and a gradual decrease in capacity after peak stress. When compressive stress distribution was substituted with an area up to the point of ultimate strain, their compression resistance performance was superior to specimens with natural aggregates due to an increase in compressive stress distribution area by about 24% for normal strength concrete (30MPa) and about 14% for high strength concrete (80MPa).

2) The proposed equation for equivalent rectangular stress blocks of concrete with electric arc furnace oxidizing slag aggregates gave an average of 1.02 and a coefficient of variation of 5.78% for the coefficient α1β1, and an average of 1.00 and a coefficient of variation of 1.81% for the coefficient β1. It provided more accurate predictions compared to other existing formulas for determining the coefficients α1β1 and β1.

3) Flexural members with electric arc furnace oxidizing slag aggregates Considering the compressive stress distribution characteristics of concrete exhibited the displacement which is smaller 2∼60% than that of specimens using natural aggregates, depending on concrete compressive strength and tension reinforcement ratio, when the tension reinforcements yield.

4) The criterions suggested by other countries’ building codes have been provided appropriate values for the ultimate moment obtained from experimental results; however, the proposed equations provides more accurate values with the an average of 1.06 and a coefficient of variation of 3.22%.

5) The specimens using electric arc furnace oxidizing slag aggregates showed an 1.33∼1.40 times larger ductility capacity for 0.3ρb, and 1.13∼3.21 times larger ductility capacity for 0.5ρb, respectively, than that of the specimens using natural aggregates under the same concrete compressive strength and tension reinforcement ratio.