Layer water-loss nomograph for 3D concrete printing

This tool integrates the evaporation from a wet face in a hall over one layer cycle. The next layer bonds to the top of this one, and a dry top bonds weakly. Use this tool to evaluate the printing conditions. It gives a measure of the risk to the bond, in grams of water per square metre.

How to use

Step 1Set the ambient temperature to match your environment.
Step 2Set the relative humidity to match your environment.
Step 3Set the expected or current printing temperature.
Step 4Set the air movement, or pick a preset.
Step 5Set the layer cycle time: the perimeter divided by the print speed, or the pause.
Step 6Read the water loss per layer against the two thresholds: 5.8 g/m².

Printing conditions

Step 1Ambient temperature, °C °C
Step 2Relative humidity, % %
Step 3Printing temperature, °C °C
Step 4Air movement, m/s m/s
Step 5Layer cycle time, min min

Advanced

Bond threshold, g/m² g/m²

The default is 10 g/m². Keita et al. (2019) found the interlayer bond unchanged at a relative water loss of 0.1 %. The threshold stands where that loss falls as a loss per unit of exposed area. It is provisional until Vertico's calibration places it.

Bond limit, g/m² g/m²

The default is 100 g/m², one decade above the threshold. At a relative water loss of 1 % about 40 % of the interlayer strength was gone. The limit stays at least a factor 1.25 above the threshold.

Wet height, m m

The height of wall below the fresh layer that is still wet. The air's boundary layer grows over that height. The default is 0.5 m.

Water loss per layer

5.8 g/m² Pass 4.2 g/m² below bond threshold0.070 kg/m²/h over 5 min

Set values

Ambient temperature 20 °C · Relative humidity 55 % · Surface temperature 20 °C · Air movement 0.20 m/s (Ventilated) · Layer cycle 5 min

Verdict
Pass below 10
Bond risk 10 to 100
High bond risk 100 and above