How is Exposed Aggregate created?

There are several ways to achieve the exposed aggregate look, here are two:


Definition - This is achieved by casting against a form surface that has been painted with retarder which retards the set of the concrete at its surface.

After the panel is removed from the form, the retarder is removed by sandblasting.

The end result is a panel with coarse aggregate exposed to the degree called for by the design.

Chemically retarded and pressure washed

Definition - This finish is achieved by the application of a chemical retarder to the surface of the form. The retarder prevents the matrix from hardening at the surface of the panel to a specific depth, controlled by the strength of the retarder. After curing (normally overnight), the unhardened layer of matrix at the surface of the panel is removed by a high pressure water washing, thus, exposing the aggregate used in the concrete.


We are going to focus on pressure washing method.  Once the cement is washed away there is very little cement holding the rocks in place.Exposed Aggregate 

Consider the picture above, notice that there is very little cement holding the rocks in place. Over time with vehicle traffic snow shovelling these rocks become loose and will start to dislodge and shed leaving holes in your aggregate.

The driveway to the right is an exposed driveway that we had to repair in the summer of 2010. This driveway was starting to unravel and come apart. Exposed Aggregate - damaged

We see this level of damage to exposed aggregate driveways everyday.  Not only can damage occur from unprotected exposed aggregate driveways over the years but the these surfaces can become dirtier and dirtier with time.

Homeowners are cautioned to seal their driveways every year.  The products that are typically used are acrylics that tend to peal off with snow shoveling within the first couple of snow falls.

We repaired this driveway with Momentum Industrial Coating Cayenne Clear. Cayenne Clear is an awesome product that is used to seal exposed aggregate driveways with much success. Exposed Aggregate - repaired

We are working with this homeowner to ensure that this repair holds as this driveway was quite damaged.

Homeowners can avoid the cost of this repair by simply coating their driveway with a quality product like the Cayenne Clear. 

This product is not the cheapest in the market place but Momentum stands behind its product by offering a 3 year warranty against peeling. 

The Cayenne Clear encapsulates the whole driveway in sealant.

The stones are not only sealed from the elements but cannot come loose because they are encased in a polyurethane sealer.
Exposed Aggregate - coated
The picture to the right is the driveway completed. Notice how the surface shines and has a wet look just like you washed it. This look will last without having to reapply every year.

An added benefit to properly coating and sealing your driveway is that it will help prevent dirt from getting trapped in the surface, which will help make your driveway look its best.

We can seed an anti-slip quartz when we apply the Cayenne Clear to prevent accidental slip and falls when the surface is wet.