• International Journal of Highway Engineering
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• v.17 no.3
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• pp.27-33
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• 2015

PURPOSES : To ensure appropriate RCC properties with sufficient strength development and workability, it is necessary to secure a proper level of consistency. It is also necessary to secure maximum dry density, which is an important factor for increasing the interaction of aggregate interlocking, leading to an augmentation of RCC strength. On the other hand, the dry density of RCC can be changed owing to the compaction conditions, water content, and particle size distribution. A Proctor test and a modified Proctor test were used for determining the optimum water content needed to achieve maximum dry density with different amounts of compaction energy. A Vebe test, on the other hand, was used for checking the level of consistency, which is important for producing a workable mixture. METHODS : To confirm the degree of compaction at various particle sizes, RCC mixtures with different sand/aggregate ratios were evaluated. The Proctor test and modified Proctor test were applied to these mixtures to check the effect of the aggregate gradation and compaction energy on the maximum dry density and optimum water content. During each test, three specimens were produced for all types of water content under each aggregate gradation. A compaction curve and the optimum water content and maximum dry density for each aggregate gradation were then obtained for both tests. The range of water content for the appropriate consistency of each aggregate gradation was determined through a Vebe test. The optimum water content was then evaluated based on this range. RESULTS : The compaction test results show that the modified Proctor test provides a higher maximum dry density and lower optimum water content compared with the standard Proctor test. For the modified Proctor test, two cases of aggregate gradation (s/a = 30% and 70%) had the optimum water contents outside of the appropriate water content range. For the standard Proctor test, on the other hand, none of aggregate gradations provided the optimum water content within the desired range. CONCLUSIONS : The modified Proctor test should be used for an RCC mixture design because it can provide adequacy between maximum dry density and consistency. Moreover, the compaction roller has become highly developed for higher compaction energy.

• Resources Recycling
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• v.23 no.4
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• pp.47-57
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• 2014

The research was conducted to analyze workability and fiber distributions of amorphous steel fiber reinforced concrete by changing fiber length and fiber addition ratio. The inverted slump cone and vebe tests as well as slump test was performed to understand the fluidity of amorphous steel fibers which have quite different appearance compared to conventional steel fibers. Test results showed that thin plate type of amorphous steel fibers required different test approach to figure out workability since the reduction of workability from slump test was different that from inverted slump cone and vebe tests. In conclusion, fluidity of amorphous steel fibers to concrete was significantly degraded as fiber length and addition ratio increase. Also, fibers space in cement matrix was apparently reduced as the increase of fiber length and addition ratios without fiber balling.