No abstract

No abstract

No abstract

In Korea, earthquakes have continued to occur even after the occurrence of Gyeongju and Pohang earthquakes of 2016 and 2017, respectively, raising awareness of earthquakes. Because earthquakes cause damage to not only structures but also humans, it is essential to improve the seismic performance and design earthquake-resistant structures to minimize earthquake damages. If the seismic performance of a structure is improved through ground improvement and reinforcement, ground response analysis should be performed considering the dynamic properties of the site of the structure. In addition, cement has been widely used as a material for ground improvement, but recently, ground improvement methods in which biopolymers are utilized for ecofriendly construction have been investigated extensively. However, studies on the changes in the dynamic properties of ground improved using biopolymers, and the ground-response analysis has not been investigated in detail. In this study, resonant column tests were performed using samples mixed with cement and sodium alginate to evaluate the effects o f ground improvement using a biopolymer. In addition, the dynamic properties of the improved samples were adopted in performing the ground response analysis, which demonstrated confirmed the ground stability after ground improvement. From the results, the ground dynamic properties, shear modulus, and damping ratio were influenced when the biopolymer and cement were mixed with the soil. Furthermore, the ground response analysis confirmed that the maximum ground acceleration on the surface decreased.

Owing to the environmental problems of the 21st century, such as global warming and soil and water pollution, environmental improvement has been recognized as an important issue. The average amount of industrial waste generated nationwide was 160,000 tons per day in 2016, which was enough to cause various environmental problems. Recycling is recognized as the most ideal treatment method because the disposal, incineration, and recycling of waste fiber, which is an industrial waste, and landfill cause many environmental problems such as subsidence, soil pollution, and carbon dioxide emission. Thus, in this study, concrete bricks were produced using waste fiber as the material, and the unconfined compressive strength characteristics according to the mixing amount and blending ratio of the waste fiber were obtained. In addition, the crystal structure of the concrete brick was visualized and analyzed using a scanning electron microscope (SEM), and the physical structure of the concrete brick made from waste fiber was obtained by X-Ray diffraction (XRD). As a result of the experiment, the uniaxial compressive strength of the concrete bricks decreased for increasing amounts of waste fiber. However, there is a value that satisfies the minimum uniaxial compressive strength standard for waste fiber incorporation, which is expected to be commercialized in the future.