3D printing construction technology is a new technology within the field of rapid prototyping, and the materials currently applicable to this technology are generally net cement or mortar, and the requirements for this mortar are that it must have good pumpability, extrudability, buildability, etc., so it is different from ordinary large-fluid pumped concrete. Microsilica as a mineral admixture also has a role for the mortar used in 3D printing construction. The following is the effect of microsilica on the performance of 3D printing mortar compiled by HSA.

Performance test method

Microsilica requirements

The average particle size should be between 0.15 and 0.20μm, the specific surface area should be 15000 to 20000㎡/kg, the water demand ratio should be 116%, and its 28d activity index should be 106%.

Performance test methods

(1) Extrudability test method

Before the test, the mixing pump and delivery pipe will be wetted with water for 2 to 3 min, after the water is completely drained, then the mixing of the printing mortar into the mixing hopper of the 3D printer, start the mixing pump, pumping speed to 8L/h, to be printed mortar by the delivery pipe from the printing nozzle evenly, continuous extrusion, with a stopwatch for 90s, weighing the process of printing mortar from the pumping pipe (the inner diameter of the delivery pipe is 18 mm, tube length of 800 mm) extruded from the printing material mass m (g), accurate to 1g.

(2) Stackability test method

After wetting the printer agitator pump with water, load the agitated print material into the agitator pump, turn on the agitator pump, wait for the print material to be uniformly and continuously extruded from the print nozzle through the delivery pipe, start the printer and load the program for testing the stacking performance. The printer executes the print command, prints the first layer, the print nozzle from the print platform height of h0 mm, after printing a straight line 200 mm long, lift h mm, print the second layer until the stacked specimen collapses, record the number of printed layers n of the specimen at the time of collapse, and then restart printing, stacking n-2 layers can be.

The effect of Microsilica on the performance of 3D printing mortar

1. The test proves that the initial and final setting time of mortar without mineral admixture is 26min and 35min respectively, while the initial and final setting time of mortar is prolonged after mixing 10% mineral powder, which is 41min and 57min respectively.
2. In the case of unchanged ratio, the apparent viscosity, yield stress and thixotropy of the mortar were increased when 5% of microsilica powder was added to replace part of the cement because of its small particle size and large specific surface area.
3. After mixing silica fume with mineral powder, the apparent viscosity, yield stress and thixotropy of mortar increase, and the cohesiveness is enhanced, so the extrudability of mortar is slightly reduced, but the printing height is increased.
4. After compounding mineral powder and silica fume, when the water reducing agent dosing is 0.3%, the retarder dosing is 0.06%, and the gypsum dosing is 3%, the tested printing mortar has suitable setting time, suitable rheological performance and better printing performance.

How to Incorporate Microsilica into 3D Printing Mortar

The addition of microsilica to 3D printing mortar requires careful consideration of the mix design and the printing parameters. Here are some guidelines to follow:

1. Use a high-quality microsilica with a particle size distribution suitable for 3D printing mortar.
2. Adjust the mix design to account for the addition of microsilica, including the water-to-cement ratio, aggregate size, and admixture dosage.
3. Test the mix design and printing parameters to ensure optimal performance, including compressive strength, flexural strength, workability, and curing time.

From the influence of microsilica on the performance of 3D printing mortar, it can be seen that, like high-strength concrete, when microsilica is mixed with other mineral admixtures and the appropriate ratio is ensured, the 3D printing mortar can be effectively made more effective. Good performance, and these are based on the quality of silica fume. The performance and quality of microsilica products of various specifications produced by Henan Superior Abrasives have reached the national standard of micro silica fume. At the same time, we can also produce micro silica products of different grades according to different purposes of customers. If necessary, please leave a message on our website , or call customer service for detailed consultation.