Title:
Influence of Recycled Concrete Powder on Rheology of Printable Cement-Based Matrixes
Author(s):
Tiago Canavarro Cavalcante, Romildo Dias Toledo Filho, and Oscar Aurelio Mendoza Reales
Publication:
Materials Journal
Volume:
121
Issue:
4
Appears on pages(s):
69-80
Keywords:
recycled concrete powder (RCP); rheology; thixotropy; threedimensional (3-D) concrete printing (3DCP); yield stress
DOI:
10.14359/51740778
Date:
8/1/2024
Abstract:
A high cement content is often found in concrete mixture designs
to achieve the unique fresh-state behavior requirements of three dimensional (3-D) printable concrete (3DPC) to ensure rapid
stiffening of an extruded layer without collapsing under the stress
applied by the following layers. Some materials with high water
absorption, such as recycled concrete aggregates, have been
incorporated in concrete mixture designs to minimize environmental impact; nevertheless, the fine powder fraction that remains from the recycled aggregate processing still poses a challenge. In the case of 3DCP, few studies are available regarding mixture designs using recycled concrete powder (RCP) for 3-D printing. In this context, this study presents the use of RCP as a filler to produce a printable mixture with low cement content. An RCP with 50 μm average particle size was obtained as a by-product from
recycled concrete aggregate production. Portland cement pastes
were produced with 0, 10, 20, 30, 40, and 50% of cement mass
replacement by RCP to evaluate its effects on the hydration reaction,
rheology, and compressive strength. It was found that the
studied RCP replacement was not detrimental for the hydration
reaction of portland cement during the initial hours, and at the
same time, it was capable of modifying the rheological parameters
of the paste proportionally to the packing density of its solid
fraction. The obtained results indicated the viability of 3DCP with
up to 50% cement replacement by RCP. It was concluded that RCP
presents good potential for decreasing the cement consumption of
3DPC, which in turn could decrease its associated environmental
impact while providing a destination for a by-product from recycled
concrete aggregate production.