Why Fly Ash Brick Pallets Bend or Crack, and How to Prevent It

Why Pallet Flatness Matters

A block machine compacts and vibrates the mix on top of the pallet. If the pallet is not flat and rigid:

• Block height varies across the pallet, so blocks fail dimensional checks.
• Vibration energy is absorbed by the flexing pallet instead of compacting the block, reducing strength.
• Green blocks crack when a bent pallet moves along the conveyor or into the rack.

6 Common Causes of Bending and Cracking

1. Thickness too low for the load

Heavier blocks, more blocks per cycle and stronger vibration all need a thicker or reinforced pallet. A pallet that suits a light fly ash brick may bend under hollow blocks or pavers.

2. Moisture absorption in untreated wood

Plain wooden boards absorb water from the wet mix and curing, swell unevenly and warp. Protective film and sealed, steel-protected edges prevent this.

3. Heat and sun exposure

Pallets left in direct sun or near steam curing can soften (low-grade plastics) or dry out and crack (wood).

4. Uneven support

Pallets resting on damaged conveyor rollers or uneven rack arms bend over time, especially when loaded with green blocks.

5. Impact and handling damage

Forklift tines, dropping pallets and stacking on uneven ground cause cracks at corners and edges.

6. Low-density material

Low-density or filler-heavy plastic pallets lack stiffness. Density and the right reinforcement matter as much as thickness.

Pallet Types Compared

For a deeper comparison of materials, see Plastic vs Wooden Brick Pallets.

How to Choose the Right Type and Thickness

1. Start with your machine: note the pallet size, model and vibration type from the manufacturer's manual.
2. Calculate the load per cycle: number of blocks × weight of each green block.
3. Consider your curing method: water curing and steam curing favour waterproof plastic or reinforced pallets.
4. Match the product to the job: light fly ash bricks suit wooden or solid plastic pallets; heavy pavers and hollow blocks suit metal or steel reinforced pallets.
5. Ask for a sample and run it through a full production and curing cycle.

Maintenance Checklist

• Clean residue after every shift so it does not build up unevenly.
• Check conveyor rollers and rack arms regularly for damage or misalignment.
• Store spare pallets flat and out of direct sun.
• Rotate pallets so the same ones are not always under the heaviest load.
• Remove bent or cracked pallets quickly; one bad pallet can spoil a whole cycle.

Frequently Asked Questions