파쇄 골재의 물리적 특성이 초고강도 콘크리트에 미치는 영향에 대한 연구

Abstract

Recently, Super high strength concretes was used commonly in Massive structure such as bridge and skyscraper and this tendency is predicted to be increased. But, rapid industrial development caused diminish of aggregate quantity which has good quality. Therefore, there are many studies about distribution of aggregates and usage of light weigh aggregates in high strength concrete. Whereas, study of natural aggregates in high strength concrete is insufficient. So, It is necessary to study about influence by using natural aggregates in high strength concrete. In this study, granite aggregates (Cheong-Ju, Yang-Ju, Ahn-Sung, Gun-San) gneiss aggregates (Hwa-Sung, Chung-Ju, Yong-In, Gong-Ju) and quartzite aggregate (Ok-Chun) were used. Every aggregates was conducted physical properties following KS standard. In addition, To analyze effect of aggregates porosity in concrete, MIP test was proceeded. Physical properties were contained density, water absorption, fineness modulus, 0.08mm passing rates and abrasion test. Most of aggregates were satisfied with Korean Standard except the abrasion test of quartzite aggregate (Ok-Chun). In case of granite aggregates, It has smaller value of F.M with large F.M value. In addition, the granite aggregates is more rough than others. In case of MIP test, the Quartzite aggregates presented smallest value and this result was similar tendency with water absorption rate. The test of concretes contained slump, air content, compressive strength and chloride penetration test. And to analyze result of concrete properties, Vickers hardness test and SEM was conducted. Every samples had about 600mm slump flow value and air content were in 1.5~2.3%. In case of compressive strength, every sample was over 50 Mpa after 3 days curing. After 56 days curing, granite aggregate concretes are increased at 10 and 18 % compared with Gneiss and Quartzite respectively. Result of chloride penetration rates was similar with tendency of compressive strength. The Vickers hardness value of granite aggregates concrete is higher than others. Especially, diminished section of hardness test in granites which is inferred ITZ were shorter than others. One of the this reason is probably shape and physical properties of aggregate. Furthermore, in the SEM result, ITZ of granites aggregate was showed denser than others clearly. From this study, Granite aggregates is mostly suitable in the high strength concrete by analyzing compressive strength and durability. It physical properties also suitable to increase compressive strength. Therefore, further research should be required to check properties over 100Mpa concretes by using various aggregate in 100Mpa high strength concrete.