Mixing protocols for plant‐scale production of concrete with superabsorbent polymers

Superabsorbent polymers (SAPs) have been investigated for their potential for internal curing, promotion of self-sealing, and self-healing of concrete structures. There has been a lack of publications concerning large-scale testing of structures with SAPs, and bringing this SAP-modified concretes from laboratory environment to plant-scale production might demand adaptations in the mixing protocols. In this paper, a reference mixture and a SAP-containing mixture were produced at a concrete plant scale and the influence of adding the polymers at different moments was investigated. The addition of SAPs directly in the truck, after the mixing procedure, showed no significant impact on the compressive strength of the concrete, but an agglomeration of particles was found in the air void analysis. The specimens with SAPs added directly in the truck presented an inferior performance in terms of shrinkage reduction when compared to the specimens with SAPs added on the materials belt, with the dry materials.