Lightweight Aggregate Self-Compacting Concrete: State-of-the-Art & Pumice Application

摘要

The scope of this study is twofold: first to present the current state-of-knowledge on lightweight aggregate self-compacting concrete (LWASCC) and second to discuss the development of pumice aggregate self-compacting concrete (PASCC) falling in the LC20/22 strength class and D1.4 density class (as per EN 206-1). Former studies have showed that the commonly accepted range of values derived from fresh-state tests on normal weight self-compacting concrete (NWSCC) is also attainable for LWASCC, the majority of which is produced using artificial lightweight aggregates. The second part of the paper presents the findings of an experimental program that aimed to assess the effect of coarse-to-fine pumice aggregates ratio on the rheological and mechanical properties of PASCC. Based on the results of this study it is verified that properly designed PASCC mixtures with a dry density in the order of 1400 kg/m~3 may be evaluated while in fresh state using the same test methods applicable for normal weight self-compacting concrete (NWSCC) and yield scores that lie within the commonly accepted ranges. If pumice aggregates are introduced in the mix in a saturated state, PASCC exhibits self-compactness similar to the one typically characterizing most NWSCC mixtures. Surface coating of fine and coarse pumice aggregates - though difficult in practice - improves workability and prolongs its retention.