Effectiveness of Paraffin-based Curing Compound for Mitigation of the Plastic Shrinkage and Related Cracking of the 3D-printed Concrete Elements

Abstract

3D-printed concrete elements are highly vulnerable to early-age shrinkage and cracking compared to conventionally cast concrete elements. Material compositions of printable concretes and complete renunciation of shuttering are responsible for accelerated capillary pressure build-up, leading to volumetric constructions of the 3D-printed layers at a very early age after extrusion and enhanced shrinkage at a later age. Shrinkage-induced cracks can severely impair the durability and appearance of 3D-printed concrete structures. The study at hand analyses the efficacy of the paraffin-based curing agent for reducing the shrinkage and cracking of 3D-printed elements and structures. Development of the temperature and capillary pressure, as well as shrinkage strains, were reported for the cured and uncured specimens. The study results show that applying paraffin-based curing agents can considerably reduce shrinkage-indued deformations of the 3D-printed elements produced even under extreme environmental conditions.

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