The development of strength is an important criterion for the production of
prefabricated concrete elements. With seasonal changes of temperature that affect the development of concrete strength, daily cycles of often 18 hours or shorter have to bemaintained. The use of Ordinary Portland Cement (OPC) promotes high early age strength, but results in a relative high impact on the environment since cement production comes with decarbonation of components and a high energy demand. With the use of supplementary cementitious materials often comes a lower rate of strength development which might be compensated by one or more of the following measures: increase of cement fineness, curing at elevated temperature, optimization of the granular skeleton and/or use of accelerators.@en

The effective production of concrete structures requires adequate control of strength development in order to realise the scheduled production cycles. Demoulding of elements can take place only when sufficient strength is gained and the production cycle has to be maintained with seasonal changes of temperature. The use of Portland Cement promotes high early age strengths, but comes with a relative high impact on the environment since decarbonation and a high energy demand come along with cement production. Supplementary cementitious materials have been widely applied to improve the sustainability of concrete but the rate of early age strength development often is compromised to some degree.@en

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.@en