Influence of Distance from the Casting Point on the Creep Behaviour

Figure 7 shows the influence of the specimens’ distance to the casting point on the creep coefficient versus time relationship for specimens with Fa/Fcr = 100 %. It was opted to only present these relationships for the maximum Fa/Fcr, since they were considered as the most critical ones. Specimens positioned near the centre of the panel (i.e. casting point) presented a lower creep coefficient, while those located in the corner of the panel had the highest creep coefficients. This aspect could be ascribed to the decrease of the concrete flow velocity with the increase of the distance from the casting point. This decrease of the flow velocity influences both the fibre dispersion and orientation along the flow profile, and, consequently, leads to quite different fibre structures within the specimens at distinct distances from the casting point. From another point of view, this observation could be also ascribed to a decrease of the matrix strength with the increase of the distance from the casting point due to some segregation of the aggregate skeleton, resulting a weaker fibre/matrix interfacial bond strength that decreases the fibre reinforcement effectiveness.

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