How are interlocking pavers made?
Earlier, we discussed the “History of the evolution of Interlocking pavers”. Now we will move on with the discussion how interlocking pavers are manufactured and what materials are used in it. We will also be studying the tests that are carried out to check the strength of a concrete paver.
Materials for the manufacture of Interlocking Pavers
Interlocking Pavers are made from namely four ingredients:
- Dry mix of gravel
- Cement
- Sand
- Desired color for aesthetic purpose
The ingredients are mixed together by adding very little water to it. The mixture is then moved on conveyor belts and then funnelled into the pavers mold. Pressure is applied to the mixture in the mold and the mold is vibrated. Pressure and vibrations cause the water to set which helps in binding the aggregates together. Further, the mold is removes and perfectly finished pavers are obtained.
Pavers are supposed to have zero slump. Having zero slump proves that the concrete is strong. After the concrete pavers are manufactured, they are sent to the laboratory to undergo slump test.
How is Slump test conducted?
8” tall cone is taken. Concrete is poured into the cone. The cone is turned upside down and removed. The amount the concrete slumps from the original 8” is measured.
For example: If it measures 7”, it is said to have 1” slump.
Three ways in which the strength of concrete can be achieved:
The ingredients in the concrete mixture have to be in correct proportions.
Water
The amount of water in the mixture has be in correct proportion. In the mixture of concrete for making paver blocks, use of water should be as less as possible. It should be used only to bind different ingredients in the mixture. Lesser the water in the mixture, stronger will be the concrete.
Cement
More the content of cement in the concrete mixture, stronger will be the concrete.
Aggregate
Preferably, the size of the aggregate should be fairly bigger. This will enhance the strength of the concrete.
Pressure Test on the concrete block
A point load is placed on the surface of the concrete block. A direct force is exerted on the surface of the block until it fails. The point at which the concrete block fails, the pressure at that point is calculated. It is called failing point.
According to industry standards, pavers need to be able to withstand a minimum of 8500 pounds per square inch. Considering the strength standards, it is to be understood that paving stone driveway is at least four times stronger than the regular concrete driveway.
In our next article, we would be discussing the “Installation Methods of Interlocking Pavers”.