This study proposed a seismic reinforcement of RC columns with non-seismic details, a fiber reinforcement method of aramid sheets and MLCP (high elasticity aromatic polyester fiber material) with different characteristics, and 4 full-size column specimens and conducted experiments. The results show that a non-seismic specimen (RC-Orig) rapidly lost its load-bearing capacity after reaching the maximum load, and shear failure occurred. The RC column reinforced with three types of aramid did not show an apparent increase in strength compared to the unreinforced specimen but showed a ductile behavior supporting the load while receiving a lateral displacement at least 1.57 to 1.95 times higher than the unreinforced specimen. The fracture mode of the specimen, according to the application of lateral load, also changed from shear to ductile fracture through aramid-based reinforcement. In addition, when examining the energy dissipation ability of the reinforced specimens, a ductile behavior dissipating seismic energy performed 4 times greater and more stably than the existing specimens.

Concrete masonry prisms are strengthened with steel fiber-reinforced mortar (SFRM) overlay and tested for compressive and diagonal tension strength. Masonry prisms are produced in poor condition considering standard workmanship for masonry buildings in Korea. Amorphous steel fibers are adopted for SFRM, and appropriate mixing ratios of SFRM are derived considering constructability and strength. Masonry prisms are strengthened with different fiber volume ratios, while numerous strengthened faces and additional reinforcing meshes are produced for compression and diagonal tension tests. Compression and diagonal tension strength are increased by up to 122% and 856%, respectively, and the enhancement effect for diagonal tension strength was superior compared to compression strength. Finally, the test results and strength prediction equations based on existing literature and regression analysis are compared.

Soil-Cement is an outstanding paving material, as it is economic, easy to construct and environmental-friendly due to its usage of natural soil. However, compared to current methods of paving, soil-cement shows low strength and low resistance on cracking, so it is necessary to supplement those drawbacks by use of some admixtures. This paper attempts to take an in-depth study of material characteristics of soil-cement mixtures with rice husk ash which is discarded as waste to enhance the strength and durability of soil-cement. To figure that out, XRF analysis was performed. From the XRF analysis results of the chemical content in rice husk ash, SiO2 is contained as much as 64.85%. Though SiO2 content is major in the rice husk ash, it is less than the amount expected. It is due to incineration temperature and time away from ideal environment for maximum SiO2 content. In addition, it figured out the strength property and durability of rice husk ash added soil-cement mixture by compressive strength test. The compressive strength test of soil-cement mixtures showed the highest strength with 10% of rice husk ash added. This suggests rice husk ash has high potential as one of pozzolanic materials.

This study is the study of the strength characteristics of the study of the natural durability enhancement materials that can reduce cracking of the concrete. The durability enhancement materials of natural were substituted 10%, 20%, 30% of cement, the results were confirmed excellent strength as the more increasing the natural durability enhancement.

Based on literature reviews, it was found that the dynamic increase factor, which is defined as the ratio of the dynamic strength to the static strength, is clearly dependent on specimen size, types, and experimental methods. It is expected that the proposed dynamic increase factor is significantly useful for numerical analysis of concrete behavior subjected to blast or impact.