Durability evaluations to assess the deterioration of reinforced concrete structures in the present have been considered only individual deterioration factors such as salt damage and carbonation. Also, indoor accelerated experiments have not been able to realize the combined deterioration factors that actually affect real concrete structures. Therefore, in this study, mixing design was proportioned with the various water-binder ratio 0.55 binder compositions corresponding to Type I cement without any supplementary materials(OPC), Type Ⅱ cement with 50% blast-furnace slag replacement (BFS50), TypeⅢ cement with 15% fly ash replacement (FA15), and ternary cement with TypeⅣ cement, 15% fly ash, and 35% slag replacement (BFS35+FA15). And this study is carried out to compare individual deterioration test with combined deterioration test and to investigate the effect of the permeation of deterioration factors such as CO₂ and chloride ion under the combined deterioration environments. After setting up various deterioration factors and levels such as carbonation, salt damage, and the repetition of drying-wetting, items such as carbonation depth, chloride ion penetration depth were evaluated under the combined deterioration environments. The results showed that carbonation depth, chloride ion penetration depth were increased according to the elapsed of ages. Also mixing design with BFS50% and BFS35%+FA15% exhibited higher durability factor than that made with OPC only.
본 연구에서는 섬유를 혼입한 모르타르 및 프리펙트 모르타르의 역학적 성능 및 내충격 성능에 대하여 평가하였다. STF, NY, PP섬유를 각각 2vol.% 혼입한 모르타르와 STF, 구조용PP섬유를 10vol.% 프리펙트하여 시험체를 제작하였다. 내충격 성능평가는 비상체의 직경 10mm, 20mm를 사용하여 충격속도 약 400m/s에서 실시하였다.
Physical properties of the geopolymer were significantly affected by the Si/Al ratio. The amorphous Si / Al ratio of fly ash that can react with the alkali activator is necessary to be calculated quantitatively. Therefore, in this study, compressive strength properties of the fly ash-based geopolymer by the Si/Al ratio was reviewed. As a result, Si/Al ratio of 2.5 exhibited the highest compressive strength, Si/Al ratio of 0.7 exhibited the lowest compressive strength. It is considered that is associated with the micro-cracks on the surface of specimen.
This study evaluated the mechanical properties and alkali silica reaction of mortar according to the mixing ratio of waste glass. As a result, as the mixing ratio of the waste glass increased, the compressive and flexible strength of the mortar decreased due to the slip of aggregate, and the alkali-silica reaction(ASR) increased. So, it is considered that research is needed to prevent slip and ASR of the waste glass aggregate in order to use the waste glass as a fine aggregate for concrete.
construction materials. For conserving natural aggregate resources, the waste concrete can be recycled as a important construction materials. Until now, the recycled aggregate manufactured from the waste concrete has been taken a side view of concrete. For the promotion of consumption of recycled aggregate, it is very important to make a study of manufacturing construction waste into good quality recycled aggregate and developing practical use for it.In this study, we investigated the evaluation for properties of recycled fine aggregate, produced by wet process, according to the ratio of the construction waste, and the effect on basic properties of recycled aggregate concrete.
Mechanical properties and durability of recycled aggregate concrete was known to decrease due to the adhesive mortar of recycled aggregate. But in this study, As the result of chloride diffusion resistance of recycled fine aggregate mortar, the mechanical properties are reduced according to the increase of the substitute ratio of recycled fine aggregate. But the chloride diffusion coefficient was almost same with natural fine aggregate mortar.
The major of this study is to investigate the experimental
equation for the estimation of compressive strength of
concrete. The results are follow.
The existing foreign equations for the estimate of
compressive strength of concrete by non-destruction
have some difference with measured data in this study.
Therefore, the relation between rebound number,
pulse velocity and compressive strength of concrete
have low correlation confficient, but combined method
show good correlation coefficient. In this study,
it is to suggest new equation for the estimation of
compressive strength to develop the application in our
countury's construction site.
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