Characterizing Rheological Effects of Corn Oil on Fresh State Concrete Mixtures for 3D Printing Applications
Additional Funding Sources
The project described was supported by the National Science Foundation via the Research Experience for Undergraduates Site: Materials for Society (Award No. 1950305) and by the Micron School of Materials Science & Engineering at Boise State University.
Presentation Date
7-2022
Abstract
In recent years, 3 dimensional concrete printing (3DCP) has proven to be a promising improvement to the construction industry due to its greater cost efficiency, as well as the greater geometrical freedom achieved from the lack of framework needed. Additionally, supplementary cementitious materials can be introduced to 3DCP to create more sustainable concrete mixture designs. Despite these advantages, a rheological challenge arises when designing concrete mixtures suitable for 3DCP applications. Rheological properties of interest in 3DCP include buildability, extrudability, pumpability, thixotropy, printing open time, and shape retention, which is related to the rate of structuration of the concrete. However, contradicting rheological properties between the pre and post extruded concrete are required for the 3D printing process - that is, the concrete must flow easily before and as it is pumped from the source and extruded through the nozzle, but must have a high enough yield stress after it is extruded so that the first layer can hold the weight of subsequent layers. To address these rheological requirements, engineers have introduced chemical admixtures which fall under broad categories of retarders, accelerators, superplasticizers (SPs), and viscosity modifying agents (VMAs). In this study, we present efforts towards utilizing industrial waste materials, specifically corn oil, as a VMA that could improve fresh state rheological properties of 3D printable concrete. It has been seen in this work that the addition of corn oil affects the yield stress and dynamic viscosity of fresh state concrete in a nonlinear fashion. Current work is being done to better understand this trend, in addition to screening further biofuel waste materials for use in 3DCP.
Characterizing Rheological Effects of Corn Oil on Fresh State Concrete Mixtures for 3D Printing Applications
In recent years, 3 dimensional concrete printing (3DCP) has proven to be a promising improvement to the construction industry due to its greater cost efficiency, as well as the greater geometrical freedom achieved from the lack of framework needed. Additionally, supplementary cementitious materials can be introduced to 3DCP to create more sustainable concrete mixture designs. Despite these advantages, a rheological challenge arises when designing concrete mixtures suitable for 3DCP applications. Rheological properties of interest in 3DCP include buildability, extrudability, pumpability, thixotropy, printing open time, and shape retention, which is related to the rate of structuration of the concrete. However, contradicting rheological properties between the pre and post extruded concrete are required for the 3D printing process - that is, the concrete must flow easily before and as it is pumped from the source and extruded through the nozzle, but must have a high enough yield stress after it is extruded so that the first layer can hold the weight of subsequent layers. To address these rheological requirements, engineers have introduced chemical admixtures which fall under broad categories of retarders, accelerators, superplasticizers (SPs), and viscosity modifying agents (VMAs). In this study, we present efforts towards utilizing industrial waste materials, specifically corn oil, as a VMA that could improve fresh state rheological properties of 3D printable concrete. It has been seen in this work that the addition of corn oil affects the yield stress and dynamic viscosity of fresh state concrete in a nonlinear fashion. Current work is being done to better understand this trend, in addition to screening further biofuel waste materials for use in 3DCP.