Investigation on the Mechanisms Governing the Robustness of Self-Compacting Concrete at Paste Level

In spite of the many advantages, the use of self-compacting concrete (SCC) is currently widely limited to application in precast factories and sihiations in which external vibration would cause large difficulties. One of the main limitations is the higher sensitivity to small variations in mix proportions, material characteristics and procedures, also referred to as the lower robustness of SCC compared to vibrated concrete. This paper investigates the mechanisms governing the robustness at paste level. Phenomenological aspects are examined for a series of paste mixtures varying in water film thickness and superplasticizer-to-powder ratio. The impact of small variations in the water content on the early-age structural buildup and the robustness of the paste rheology is investigated using rotational and oscillating rheometiy.