Technical InformationEXPANDO is a non-explosive, non toxic chemical demolition agent that safely and silently cracks rocks and concrete in four easy steps: Drill, Mix, Pour and Expand!


Preparation before using Expando


First measure the temperature of the jobsite, demolition agent, water, stone/concrete and container to ensure temperatures are in accordance with compliance requirements. Next, select the correct Expando product range for the jobsite temperature.


The following objects need to be prepared:


  • Demolition agent
  • Clean and cold water
  • Plastic or metal bucket
  • Beater or wooden rod for mixing
  • Safety goggles
  • Rubber gloves
  • Dust proof mask (recommended)
  • Helmet (recommended)
  • Thermometer (recommended)


Step 1.

Drill holes in the rock or concrete where the material is to be cracked.The distance between holes will vary depending on type of material. Generally, the closer the holes, the quicker it is to crack the material.The diameter of the holes will dictate cracking results – holes that are too small may result in sub-optimal performance, while holes that are too big may cause blowout shots.Please note: do not exceed 40mm diameter drill sizeThe following figures are for reference purposes only. For best results, it is advisable to carry out experiments or tests with Expando before starting work.



Step 2.

Expando expansive mortar must be thoroughly mixed with clean cold water before use. Gradually add one bag of Expando to 1.5 – 1.7 litres of water. Stir until you obtain a smooth lump-free slurry.Use only open pails or containers for mixing. Narrow necked containers must not be used.Avoid adding extra water, as this may reduce concentration and effectiveness of the mix.Avoid mixing more than 10kg of Expando at any one time


Step 3.

Pour the freshly mixed slurry into predrilled holes within ten minutes of mixing. Do not look directly into filled holes for the next 2 – 6 hours.Tamp the mortar filled into the holes by using a slightly smaller stamp stem. For long holes, tamp the mortar section by section to remove trapped air pockets.For horizontal and slant holes, insert a slightly smaller plastic pipe into the hole and fill the mortar into the pipe slowly, withdrawing the pipe from the hole simultaneously. Tamp the mortar section by section to remove trapped air pockets.Another method for horizontal holes is filling sausage shaped plastic bags. Tie the bags off and insert them into the horizontal holes. The benefit of this method is that it will retain the fluid in the horizontal hole.



Step 4.

The reaction time of EXPANDO to crack stones varies from 24 to 76 hours. This varies depending on material being cracked, the hole design and the ambient temperature at the job site. Expando continues to increase in pressure for up to 5 days.


Caution: The chemical reaction of Expando and water generates heat. If the reaction goes too quickly the temperature can be above the boiling point of water before all the water has chemically combined with Expando. This can result in a steam driven explosion which blows the Expando mortar from the holes with sudden force.


Expando, once mixed and poured into holes, expands as it slowly sets gradually applying expansive stress up to 14,000 PSI.


Initially propagation occurs then the crack widens. When multiple holes are filled adjacent to each other, the cracks propagate to join with the neighbouring holes. This allows you to determine the exact direction of the cracks with your hole pattern designs.


The hole pattern design must allow the material to move to free space when Expando expands as shown below. Failure to provide free space will result in unpredictable material movement. It is recommended that you plan your work so you are always working away from a free space (this gives the broken piece of material somewhere to move to).

expando NZ

This is a mockup. Publish to view how it will appear live.