Why is compaction of RCC so important?
Similar to conventional concrete, RCC must be consolidated or in the case of RCC, compacted in order to achieve the desired performance characteristics. The degree of compaction of RCC has a direct role on its ultimate strength and durability. Because of RCC’s very dry consistency and reduced workability, adequate compaction of RCC can be more difficult to achieve than with conventional concrete. Compaction of RCC depends upon many variables including materials used, mixture proportions, mixing, transporting and placement methods used, compaction equipment, lift thickness and time of compaction. The best performance characteristics are obtained when the RCC is reasonably free of segregation and compacted throughout the entire lift at, or close to, maximum density. Research studies including the one below have shown that the strength of RCC drops appreciably as the density drops. (Figure 1). Figure 1. Strength vs. density for various RCC mixtures (Schrader) Data from the figure indicate
