Effect of Environmental Conditions on Shrinkage-Induced Cracking of 3D Printed Mortar (2024-11)¶

In 3D concrete printing, the removal of formwork compared to traditional casting has caused an issue regarding the early exposure of the concrete surface to the environment. This early exposure can lead to the immaturity of strength development in the early stages and shrinkage-induced cracking due to excessive water evaporation and lack of coarse aggregates in typical mixes for 3D concrete printing. These challenges highlight the need for careful consideration of environmental factors and the development of specialized techniques to mitigate their impact on the structural integrity of 3D- printed concrete structures. This study investigated the influence of environmental factors (temperature, humidity, and wind) on strength development and plastic shrinkage of a 3D-printed mortar at very early ages. The initiation and development of shrinkage-induced cracks were also studied on 3D-printed samples exposed to different environments. Temperature fluctuations can cause expansion and contraction of the concrete material, leading to internal stress and potential cracking. Humidity levels also play a significant role, as moisture absorption and desorption by the concrete can affect its shrinkage behaviour and strength development. Additionally, exposure to elements such as wind can further exacerbate water evaporation and cause the deterioration of the printed structure. By delving deeper into the environmental factors that impact shrinkage-induced cracking, this study aims to provide valuable insights that can inform the development of more resilient and sustainable 3D-printed concrete structures.