The effects of compaction methods and mix parameters on the properties of roller compacted concrete mixtures

Abstract

Despite the wide use of RCC, there is no specific compaction methodology developed to simulate the site conditions in the laboratory. Yet, there are few compaction methods that are generally used to produce RCC specimens in the laboratory environment. The most common methods are the vibrating table and the vibrating hammer found in ASTM, and the modified proctor and Superpave gyratory compactor (SGC), which are suggested to be standardized. However, it is not well known how these different compaction techniques can reflect the properties of RCC in situ. In this study, RCC mixtures which consist of two different cement dosages and two types of aggregate gradations were compacted by the four laboratory compaction methods mentioned above, to investigate the effect of laboratory compaction methodology on the physical properties and mechanical performance of RCC. The first three methods are the ones commonly used in the literature, while the fourth method (SGC) is thought to best represent the field compaction conditions with the kneading action. Moreover, regressions models were derived for each of the compressive and splitting tensile strengths based on the mix parameters. The statistical analysis showed that the compressive and splitting tensile strengths were highly affected by the compaction ratio, then by the cement content. The water content seemed to be dependent on the compaction ratio and had a small effect on the strengths. The ideal laboratory compaction methods in terms of strengths and compaction ratio within the acceptable Vebe consistency time were determined as the SGC first and the vibrating hammer second.