Effect of surface moisture on inter-layer strength of 3D printed concrete

The hard, strong and durable cement−based product required by the user is only achieved following a period of plasticity but the attention paid to its fresh properties is small, despite the far−reaching effects of inadequate fresh performance. Pumping, spreading, moulding and compaction all depend on rheology and thanks to an increasingly scientific approach it is becoming possible to predict fresh properties, design and select materials and model processes to achieve the required performance. Rheology is now seriously considered by users, rather than being seen as an inconvenient and rather specialised branch of cement science.

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The rheology of fresh cement and concrete - a review

Lubrication layer properties during concrete pumping

This paper provides a comprehensive review of the material behaviour for extrusion-based concrete 3D printing spanning from the early age to long-term performance. We begin with a discussion on the recent progress on the understanding of early-age behaviour. Following this, the mechanical response in the hardened state, and the different strategies to introduce reinforcement are reviewed. Finally, we present insights and perspectives on the transport mechanisms in printed concrete to assess the long-term performance, and also discuss the overall impact of construction by concrete 3D printing on sustainability.

Phillip B. Bamforth

Papers

Tests to Establish Concrete Pumpability