3D printing technology in building construction

1. BY:
Vodepalli Manaswini
NITWarangal.
3D PRINTING TECHNOLOGY IN
BUILDING CONSTRUCTION

2. CONTENTS
 Introduction
 Types Of 3D Printing Technologies In Construction
 Current Examples
 Framework For Laboratory Testing Of Printing
Concrete In Fresh State
 Testing Procedures
 Advantages of 3D printing

3. IS IT REALLY POSSIBLE TO PRINT A
BUILDING…?
And The Answer Is YES!

4. 3D CONCRETE PRINTING
 3D concrete printing is an emerging technology that combines
digital technologies and new insights from material
technologies to allow free-form construction without the use of
formwork.
 It is a type of additive manufacturing technique where the
construction is through layer-by-layer addition of material.

5.  It involves fabricating a predesigned building element
in 2D layers on top of each other, the repetition of
which results in a 3D model.
 The concrete, which is poured out of a printing
nozzle, does not require any formwork or subsequent
vibration

6. Two processes currently leading
the 3DCP field are :
(1) The Extrusion based Single
Deposition Nozzle Concrete
Printer which is similar to fused
deposition modeling. Contour
Crafting is another technology
where concrete is extruded
against trowel; and
(2) Powder deposition process
where the “ink” is deposited on a
powder bed.

7. EXTRUSION-BASED 3D CONCRETE PRINTING
 The extrusion-based 3DCP is similar to the fused deposition modeling
used in polymer and metal technologies.
 Contour crafting is one of the proprietary terminologies used for the
layered fabrication technology
 It is based on extruding a cement-based concrete against a trowel
that allows a smooth surface finish created through the build-up of
subsequent layers

8. CURRENT EXAMPLES OF EXTRUSION-BASED 3D
CONCRETE PRINTING ELEMENTS/STRUCTURES
(A) The two-story villa 3D printed by Huashang Tengda company; and (B)
the novel nozzle of the giant 3D printer
 The frame of the house, including conventioinal steel reinforcements and
plumbing pipes, were first erected
 Their giant 3D printer has a sort of forked nozzle that simultaneously
lays concrete on both sides of the rebars, swallowing it up, and encasing it
securely within the walls

9. The first 3D printed modular
reinforced concrete beam of
about 3 m
The Y-Box Pavilion, 21st-century
Cave 3 m tall structure

10. Onsite 3D printed house by Apis Core. (A) Construction using
a mobile 3D concrete printer; (B) house exterior
3D printed bridge

11. POWDER-BED-BASED 3D CONCRETE PRINTING
 In the powder-bed process, a thin layer of powder is
spread over the powder bed surface first. Once a layer
is completed, binder droplets are selectively applied on
the powder layer by a print-head causing powder
particles to bind each other
 The binders are deposited only in places where the
building material should become solid and the rest is
kept loose and removed at a later stage.
 This uses D-shape 3D printing construction technology

12. Sculpture by D-shape process

13. FRAMEWORK FOR LABORATORY TESTING OF PRINTING
CONCRETE IN FRESH STATE

14. MATERIALS THAT CAN BE USED
• BinderPortland cement
• Sand with nominal maximum
aggregate size of 4.75mm
Fine aggregate
• to achieve the required
flowability for the mixtures(e.g.
polycarboxylate-based)
High-range
water reducing
admixture
(HRWRA)
• used to increase the plastic
viscosity and cohesion of
printing mixtures.
Viscosity
Modifying admi
xtures
(VMA)

15. • as a shrinkage reinforcement
Fiber
reinforcement
• improves cohesion of fresh concrete
and the mechanical strength and
impermeability of hardened concrete
Supplementary
cementitious
materials
• improves the cohesionNanoclay

16. TESTING PROCEDURES
 In order to ensure that the achieved mix is the
optimal one, several tests had to be conducted
taking into consideration the target parameters to
be achieved.
 The five parameters (extrudability, flowability,
buildability, compressive strength, and open time)
together contribute to the success of the printing
process.

17. FLOWABILITY TEST
 Flowability could be defined as the ease with which concrete flows in a
system under given conditions.
 Flow of each mixture can be determined using a flow table , which
involves a mold being filled with mortar and then compacted.
 The mold is subsequently lifted away from mortar and the table is
immediately dropped 25 times in 15 seconds.
 The flow is the resulting increase in average base diameter of the mortar
mass expressed as a percentage of the original base diameter.

18.  Flow value reduces upon addition of supplementary
cementitious materials like silicafume and also with fiber
reinforcement.
 A considerable increase in viscosity and cohesion of
mixture will be observed because of a small addition of
nanoclay

19. PRINT QUALITY
 “print quality” refers to the properties of a printed layer, such
as surface quality and dimensional conformity/consistency,
when using a specific printing mixture.
 A printing mixture could be considered acceptable when three
requirements are satisfied:
(1) The printed layer must be free of surface defects, including
any discontinuity due to excessive stiffness and inadequate
cohesion;
(2) the layer edges must be visible and squared (vs round
edges); and
(3) dimension conformity and dimension consistency must be
satisfied by the printed layer.
Based on these three proposed criteria, the print quality of a
mixture can be evaluated and an acceptance decision can be
made

20. Discontinuity (tearing) in the printed layer due to excessive
stiffness of the mixture.
(A) Variations in width of printed layer using different mixtures at
the same printing speed (dimension conformity)
(B) Variations in width of a single layer (dimension consistency).

21.  Five measurements should done along each
printed layer to assess the dimension conformity.
 Studies show that 10% error in the target width was
a reasonable range for accepting or rejecting
printed layers.

22. SHAPE STABILITY
 Three main sources of deformation which apply to a deposited
layer: (1) self-weight; (2) weight of the following layer(s) to be
printed on top of it; and (3) the extrusion pressure.
 Shape stability is a critical property of fresh concrete printing,
which refers to the concrete’s ability to resist deformations
during layerwise concrete construction
 Two different test methods, namely the layer settlement and
cylinder stability tests, were developed and carried out to study
the shape stability of printing concrete.

23. LAYER SETTLEMENT TEST
 In this test, two concrete layers were printed on top
of each other with a specific time gap
 photos were taken before and after the second
layer was printed.
 A software was used to analyze the photos and to
measure layer settlement.
 The average of five readings for a printed layer was
reported as a test result. Studies show that shape
stability of a printed layer improves over time

24. A five-layer printed specimen with interlayer time gap of 19 min.

25. CYLINDER STABILITY TEST
 There are five steps in the cylinder stability test procedure:
(1) the semicylinders are fixed in place and locked, and a concrete
layer of 40 mm is placed;
(2) using the tamping rod, the layer is consolidated by rodding 15
times and evenly distributed;
(3) the same procedure is repeated for the second layer and
excessive concrete is removed from the top
A) 3D printed parts for cylinder stability test. (B) Cylinder stability test.

26. (4) the two semicylinders are unlocked and gently removed and
any possible change in height as a result of self-weight is
measured and recorded;
(5) a load of 5.5 kg (equivalent to a 4.77 kPa stress) is applied and
the resulting deformation in the fresh concrete cylinder is
measured in terms of change in height.
The main advantage of this test (compared to the layer settlement
test) is eliminating the need to print concrete layers, leading to
saving time during the mixture design phase.

27. PRINTABILITY WINDOW
 Two important parameters related to the printability
window include the printability limit and blockage
limit.
 Printability limit is the longest period during which
a mixture can be printed with acceptable print
quality.
 Blockage limit refers to the longest period of time
when a mixture can remain in the nozzle before the
concrete hardens and blocks the extrusion.

28. COMPRESSIVE STRENGTH TEST
 The concrete’s compressive strength is of
particular importance due to the fact that the
printing mechanism pours the structure in layers
rather than in its entirety at once.
 Since the printing process happens only in a
matter of minutes and setting time is assumed to be
instantaneous, the targeted strength and strength
gain should be high.

29. ADVANTAGES
When compared with conventional construction processes, the
application of 3D printing techniques in concrete construction may offer
excellent advantages including:
 Reduction of construction costs by eliminating formwork.
 Reduction of injury rates by eliminating dangerous jobs (e.g., working
at heights), which would result in an increased level of safety in
construction.
 Creation of high-end, technology-based jobs.
 Reduction of onsite construction time by operating at a constant rate.
 Minimizing the chance of errors by precise material deposition.
 Increasing sustainability in construction by reducing wastages of
formwork.
 Increasing architectural freedom, which would enable more
sophisticated designs for structural and esthetic purposes.
 Enabling the potential of multifunctionality for structural/architectural
elements by taking advantage of the complex geometry

30. Contour Crafting was selected by NASA for its Innovative
Advanced Concepts (NIAC) to explore the use of building a
Lunar Settlement infrastructure

31. REFERENCES
 Jay G. Sanjayan, Ali Nazari and Behzad Nematollahi, 3D Concrete Printing
Technology , 2019.CHAPTER 2 :Performance-Based Testing of Portland
Cement Concrete for Construction-Scale 3D Printing.
 T.T. Le, S.A. Austin, S. Lim, R.A. Buswell, A.G.F. Gibb, T. Thorpe, Mix design
and fresh properties for high-performance printing concrete, Material.
Structure. 45 (8) (2012) 1221-1232.
 J. Pegna, Exploratory investigation of solid freeform construction, Automatic.
Construction. 5 (5) (1997) 427-437.
 J. Zhang, B. Khoshnevis, Optimal machine operation planning for
construction by contour crafting, Automatic. Constructio. 29 (2013) 50-67.
 A. Perrot, D. Rangeard, A. Pierre, Structural built-up of cement-based
materials used for 3D-printing extrusion techniques, Material. Structure. 49 (4)
(2016) 1213-1220.
 Apis Core, The first on-site house has been printed in Russia. On-line: http://
apis-cor.com/en/about/news/first-house., (accessed 20.03.17).
 F. Bos, R. Wolfs, Z. Ahmed, T. Salet, Additive manufacturing of concrete in
construction: potentials and challenges of 3D concrete printing, Virtual Phys.
Prototyping 11 (3) (2016) 209-225.