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The importance of compacting pavers after laying them cannot be overstated. Skipping this step in the process can lead to a weaker pavement surface and the ultimate failure of the jointing compound. Also, doing this step without the proper equipment can lead the the scuffing of pavers and destroying the surface of the pavers. There is not a lot that needs to be done to avoid these, but it is an easily overlooked step in the process of installing interlock that will stand the test of time.
Importance of Compacting Pavers
Regardless of the jointing compound that you choose to install or the paver base that you opt for, the pavers that you install need to be compacted after laying them. This is achieved using a plate compactor and a protective layer between the compactor and the pavement in order to prevent scuffing and damage to the pavers themselves. The reasons why this is an important step in the process of installing pavers are:
- Bedding the Pavers
- Consolidating the Jointing Compound
- Vertical Interlock
Compacting the pavers into the bedding material allows for a small amount of the bedding layer to move up into the joint of the pavers. This seats the pavers into the bedding material contributing towards the strength of the overall interlock pavement system and the vertical interlock that the pavement holds.
Without the compaction of the pavers when the jointing compound is being installed, the material for the joints would not make it to the very bottom of the joint. If this step is skipped, true vertical interlock is not achieved and the pavement is not as strong as it could be. Additionally, this will lead to inevitable failure of the jointing material as the gap between the bedding material and jointing compound eventually causes the erosion through lubrication and load of that material.
As the jointing compound is swept into the pavers, the material chokes itself out as it makes it way down the joint. These larger granules in the jointing material get stuck on their way down and cause a blockage with further material ensuring that the jointing material does not make it all the way to the bottom of the joint. This is why it is important to sweep the jointing material and then use a vibrating compactor to create that vibration to allow the material to consolidate to the bottom of the joint. Then you can complete a top up of the joint with more jointing material and continue this process until the material has come 1/8 inch below the top of the paver or bottom of the chamfer. Following these steps will ensure the strength of the pavement surface through the next point here.
Pavers achieve rotational, horizontal, and vertical interlock when installed properly which is what makes it such a strong pavement solution when compared to alternatives. Vertical interlock is achieved through the jointing compound and bedding the interlock into the screed layer. This is completed through the compaction of pavers once they are installed and the consolidation of that joint material to the bottom of the joint. When the pavers are compacted, a small amount of that bedding layer creeps into the joint from the bottom up while the jointing material makes its way from the top down. This material in the joints of the pavement prevents the shearing force of the pavers from the dynamic load that travels on the surface of them.
How to Compact Pavers
Pavers can be compacted through the vibratory impact of a plate compactor with a protective layer between the compactor and the pavement surface or a paver rolling compactor that protects the surface with its rolling pads.
If you are using polymeric sand or a similar jointing compound, you can complete the compaction of the pavers to seat them into the bedding layer and the consolidation of the jointing material in the same compaction. This step always follows the installation of an edge restraint. Follow these steps:
- Sweep the jointing material over the surface following the manufacturer’s guidelines and filling the joints of the pavers. Sweep off any excess material cleaning the surface of any granules of the material to avoid scuffing the pavers in the next step.
- Compact the pavers using a plate compactor and a protective pad or a paver roller compactor. Make sure there is no dried mud or gravel on your compactor that will loosen and fall onto the paving surface as you move your way around. Move your way around the surface from the outside working your way in and then in horizontal or vertical lines throughout the project.
- Top up the joints with more jointing compound coming 1/8 inch below the top of the paver or bottom of the paver chamfer. Continue with the previous step and this step as many times as necessary to achieve this final level of jointing material. Smaller joints will require this to be done multiple times.
- Activate the sand if you are installing polymeric sand according to the manufacturer’s guidelines or follow the finalizing steps of the jointing compound you are using.
How to Compact Pavers Without a Plate Compactor
It is not recommended to compact pavers without a vibrator compactor as described above as the same impact cannot be achieved in the same efficient and effective fashion. However, in some cases you may not have access to a compactor or you may need to get into some tight spaces to complete the compaction of pavers and consolidation of the jointing material. In these cases you can use a rubber mallet that will not leave marks on the surface of the pavers to compact the pavers. You can use a small pad to place over the pavers and whack away at the surface of the pad to allow for a consistent surface level. If you do not do this, you may hit a corner of a paver and cause that corner to sink lower than the other pavers around it causing an imperfection. Alternatively, you can also use a hand tamper with a protective layer taped to it or have a pad on top of the pavers to complete this step. Both of these options are inefficient and not quite as effective as using a vibratory compactor to complete this step.
How Much Will Pavers Sink When Compacted
This depends on your bedding layer and the depth of your bedding layer. This layer should not exceed one inch. When using concrete sand as your bedding layer at 1 inch, you can expect as much as 1/4 inch settlement. When using High Performance Bedding as your bedding layer at 1 inch, you can expect as much as 1/8 inch settlement.
This difference is due to the self-compacting nature of High Performance Bedding. Its crushed and clean angular design allows for the chips to align themselves up to 90% compaction without any mechanical compaction.