Rheological- and Pumpability-Analysis of Sustainable 3D Printing Mortars Incorporating Recycled Sand (2024-11)¶

This paper presents a comprehensive investigation into the rheological behaviour and pumpability of a mortar designed for 3D printing, incorporating fine recycled aggregates (recycled sand) sourced from construction and demolition waste. The research addresses the growing demand for sustainable construction materials by exploring the viability of recycled sand in 3D mortar printing applications. The study aims to modify a highly thixotropic reference mortar for 3D printing by substituting natural sand with recycled sand. Various aggregate-tobinder (a/b) ratios are used to assess their influence on the mortar’s rheological properties and pumpability. The methodology extensively employs rheological oscillatory tests conducted with an Anton Paar MCR102e rheometer to obtain the storage modulus (G’) and loss modulus (G”) evolution over time for each mixture. Additionally, oscillatory step tests are conducted to measure the degree of thixotropy exhibited by the mixtures. The findings of the Sliding Pipe Rheometer (SLIPER) are instrumental in characterizing the slip layer’s rheological properties, providing essential insights into the pumpability of the mortar.