International Research: Evaluating 3D Printing Concrete with Sisal Fibers

Share this Article

Researchers from France and the UK are delving into 3D printing in construction and experimenting with parameters in materials. Releasing their findings in ‘Rheological properties of 3D printing concrete containing sisal fibres,’ the authors explain positive and negative effects as they studied impacts on cement.

Formworks are a major factor in the cost of concrete construction today, so the benefits intrinsic to 3D printing such as greater affordability overall, rapid speed, customization, and more make the technology enticing to industrial users. Currently, the most popular methods used are D-shape or binder jetting, and concrete printing via extrusion. For this study, the researchers used fly ash and limestone powder as a binder with Portland cement, and investigated the following for impacts on the printable mortar:

  • Fly ash
  • Limestone powder (LS)
  • Percentage of natural sisal fibers (NF)
  • Dosage of superplasticizer (SP)
  • Viscosity modifying admixture

“The rheological parameters were evaluated by the static yield stress using the cylindrical slump test,” explained the researchers.

Notations for estimating the yield stress with the slump test

Reminding us that any type of work with cement is ‘strongly time-dependent,’ the authors point out that timing must be consistent in experimentation with all sample compositions or comparisons would be void. Dry materials, binders, and water were mixed in a blender, and then both natural fibers and VMA were added. Afterward, the mortar was evaluated for rheological characterization.

Influence of FA on flow table spread and estimated yield stress

As two different types of mortar were evaluated (one with 100 percent binder and the other made of 24% of FA of replacement of cement), the researchers noted a reduction in the flow table spread with FA, but only slightly so—and it also had an impact on the ‘estimated yield stress similarly as the slump flow.’ With extrusion, the LS mix did not hold up in sustaining the layers. Previous research has also shown that the use of LS has been the possible cause of ‘segregation’ in cement past.

“Consequently, it has been demonstrated that binder only made with cement and limestone powder was not suitable to be applied in 3D printing processes with mortar,” said the researchers.

Influence of VMA on rheological properties

The addition of increased SP reduced the estimated yield stress substantially, influencing ‘workability, consistency, and printability.’ In adding VMA, the team noted a reduction in the following: flow table spread, penetration, increase in estimated yield stress. These types of mixes offer better viscosity, along with stable layer adhesion.

Influence of VMA on extrusion and visual observation

“The addition of sisal fibers (NF) from 0.6 to 1% of binder, reduced the flow of the mortar by improving its cohesiveness with a denser network of fibers. Indeed, with the addition of higher amounts of NF, the yield stress increased, and the fresh properties decreased,” concluded the researchers.

“Appropriate workability, good segregation and bleeding resistance, easy extrudability and great printability and buildability were required in order to apply 3D printing processes to cement-based materials. Indeed, extruded layers must maintain it-self and might not deform under supplementary layers’ load. It also means that layers must bond together to avoid voids, cold joints and other weakening issues.”

Compositions and fresh and rheological properties

3D printing with cement and use of such techniques and materials in construction has resulted in many studies as well as dynamic projects over the past few years especially, from investigating different binders with low conductivity to the use of 3D printed concrete foam panels, self-healing materials, and so much more.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Rheological properties of 3D printing concrete containing sisal fibres’]

Share this Article


Recent News

Volume Graphics Releases Updated Version of CT Scan-Based Testing & Analysis Software

How Conformal Will Change Design and 3D Printing



Categories

3D Design

3D Printed Art

3D Printed Guns

3D Printer Reviews


You May Also Like

3D Printing Webinar and Event Roundup: May 16, 2021

Even as we get closer to the official start of summer, that doesn’t mean the amount of webinars, virtual events, and live events are going down; in fact, the opposite...

3D Printing Webinar and Event Roundup: May 9, 2021

We’ve got another full week of AM industry webinars and events to tell you about, so let’s not waste any time on the introductions—jump right in! SPE’s ANTEC 2021, with...

Link3D Launches AMWatch for Monitoring and Controlling 3D Printing Variables

On the heels of its likely acquisition by Materialise, Link3D is continuing its development of technology for manufacturing execution systems (MES). The latest news from the company is the launch...

Materialise Opens €7.5M Metal 3D Printing Facility

Belgian 3D printing provider Materialise is growing. Not only did it recently announce an option to acquire MES software developer Link3D, but the company has also opened a new 3,500...


Shop

View our broad assortment of in house and third party products.