Product Data Sheet Safety Data Sheet Show all documents

Sikacrete®-751 3D

1-part accelerated micro-concrete for 3D printing

Sikacrete®-751 3D is a 1-part accelerated micro-concrete for use with 3D concrete printing robot or gantry printers.

  • Fast absorbing, suitable for continuous and static mixers
  • Easy to use, just mix with water
  • Adjustable consistency, for temperature variations
  • High thixotropic consistency, to maintain shape after extrusion
  • Accelerated, for high stacking and building up layers
  • A faster setting, for moving objects sooner
  • Low shrinkage, to reduce potential for cracking
  • Small grain size, for reduced equipment wear
  • Optimised grading, for smooth appearance
Product Data Sheet Safety Data Sheet Show all documents

Usage

For precision concrete printing of 3D objects and components for:
  • Buildings
  • Civil engineering structures
  • Moulds and forms
  • Art, craft and visual displays
  • Interior and exterior use
 

Advantages

  • Fast absorbing, suitable for continuous and static mixers
  • Easy to use, just mix with water
  • Adjustable consistency, for temperature variations
  • High thixotropic consistency, to maintain shape after extrusion
  • Accelerated, for high stacking and building up layers
  • A faster setting, for moving objects sooner
  • Low shrinkage, to reduce potential for cracking
  • Small grain size, for reduced equipment wear
  • Optimised grading, for smooth appearance

Packaging

25 kg bag

1000 kg bag

Colour

White powder

Product Details

Product Information

Composition / Manufacturing

Portland cement, selected aggregates and additive

Shelf Life

9 months minimum from date of production

Storage Conditions

The product must be stored in original, unopened and undamaged sealed packaging in dry conditions.  For consistent printing quality it is recommended to store the material at temperatures between +10 °C and +25 °C.
Always refer to packaging

Maximum Grain Size

~1 mm

 

 

Density

2.140 kg/l
Technical Information

Compressive Strength

water addition 14.5 %

Conditioned 24 h at 20 °C

30 MPa

Conditioned 28 d at 20 °C

50 MPa

Modulus of Elasticity in Compression

Cured 28d at 20°C

31 GPa

Tensile Strength in Flexure

water addition 14.5 %

Conditioned 24 h at +20 °C

3.5 MPa

Conditioned 28 d at +20 °C

10 MPa

Application

Application Information

Layer Thickness

6–15 mm

Layer thicknesses are subject to the equipment and printing procedure and it is recommended to make a test to check suitability

Product Temperature

Minimum

+10 °C

Maximum

+25 °C

The material and water temperature plays a significant role in the printing process.  Having a constant, or reducing significant variations during application will help maintain a consistent quality of printing.

Ambient Air Temperature

Minimum

+5 °C

Maximum

+30 °C

Mixing Ratio

14–15 % water (by weight of powder)

Pot Life

+10 °C

20 minutes

+20 °C

15 minutes

+30 °C

10 minutes

Pot life is based on the temperature of the material after extrusion and indicates when the material is starting to stiffen.  Agitating the material during this time will prolong the pot life.

Initial Set Time

+ 5 °C

80 minutes

+20 °C

45 minutes

+30 °C

35 minutes

Final Set Time

+5 °C

90 minutes

+20 °C

60 minutes

+30 °C

45 minutes
Consumption

Yield

~13 litres per 25 kg.

This figure is theoretical and does not allow for any lost material during the mixing or pumping process
Application steps

MIXING

STATIC MIXERS

  1. Use a suitable forced action pan mixer for cementitious materials capable of mixing more than a single 25 kg bag per mix.
  2. Add the recommended amount of clean water with the powder and mix, check the corners of the mixer for no dry powder. Mix for a minimum of 2 minutes until the material is homogeneously mixed and place the material into the pumping equipment.

CONTINUOUS MIXERS

  1. Determine the required printing consistency by adjusting the water addition on the equipment as a flow rate in L/hr.
  2. Check the water content using the pan test heating method or microwave technique (according to Austrian Standard).

A typical printing consistency is in the vicinity of 140 to 150 mm in a spread-flow test according to EN 13395-1. For further assistance contact your local Sika technical services department.

APPLICATION

3D concrete printing is a manufacturing process using mixing, pumping and robotic placement to apply the printed concrete. All these factors play a significant role in achieving optimal results of the finished concrete component and therefore pre-trials and tests must be carried out before final manufacturing of the finished components.

  • Use a good quality Pump Primer to prime pump lines.

  • In the event of blockages, rinse equipment and pump lines immediately with clean water

  • Continuously monitor the pot life of the mixed material.

  • Do not allow mixed material to stand in warm temperatures.

  • Keep pump lines wetted and cool.

  • Use warm water at low temperatures and cold water at high temperatures to maintain application performance.

  • For operational maintenance, refer to the equipment instructions.

CURING TREATMENT

Discolouration of printed objects

Note: Condensation due to certain curing methods and curing agents may cause some discolouration to the surface appearance.

  1. Carry out pre-trials with the chosen curing method or agent.
  2. Cure the Product in the prescribed ambient conditions with a minimum of 40% relative humidity to prevent too early drying of printed objects.
  3. Do not cure newly printed objects outside in the direct sun or windy conditions.

The standard rules of good concreting practice, concerning production and placing must be followed.

 

CLEAN UP

Clean all tools and application equipment with water immediately after use. Hardened material can only be removed mechanically.

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