Page 14 - ICJ Jan 2026

TECHNICAL PAPER

(a) Laser-based 3D printing representative diagram (b) Prepared sample
Figure 13: Laser-based 3D printing using a heat-cured geopolymer

previous trials showed that during longer heat exposure, the Optimum mixing sequence for low-moisture mixes:
depth of the printed layer increases marginally due to poor heat Compression-based fly ash bricks are prepared using low-
conductivity. Higher exposure temperature results in shrinkage moisture mixes. Two different mixing methods were explored
cracks. In the previous trials, stable layers could be printed up at different water-binder ratios to compare the effect of
to 3 mm in thickness. Furthermore, in a separate experiment mixing sequence on the quality of bricks . First mixing
[33]
to study the interlayer bonding, the sample was coated with a sequence used dry blending of solids, followed by water
second layer of geopolymer and heated. It was observed that a mixing (Figure 14) . The second mixing sequence used
[33]
small coating thickness caused shrinkage cracks, while a large
coating thickness resulted in poor interlayer bonding. Further the preparation of the binder slurry and coating it over the
[33]
studies are needed to figure out a method of controlling layer aggregates (Figure 14) . Results showed that dry blending
thickness. followed by water addition produced better quality bricks, in
terms of strength, density, water absorption, impact energy and
[33]
5. IMPROVING THE SCIENCE OF CONCRETE drying shrinkage . Here, the poor strength and compaction
MIXING AND COMPACTION in the second mixing method suggest that the slurry failed to
distribute within the mix due to reduced flowability resulting
In addition to materials, the production process has a from low moisture. Therefore, for the adopted mix, the first
significant impact on the properties of building products. mixing method is recommended for brick manufacturing, which
Several investigations have been carried out to improve the
product quality through the preparation process. Some notable is the typically adopted industrial method.
observations have been included in the manuscript.

Figure 14: Different mixing sequences for the preparation of low-moisture fly ash bricks

76 THE INDIAN CONCRETE JOURNAL | JANUARY 2026