Exposed Aggregate Driveways

February 3rd, 2011

Wilmington, NC home builder Mark Johnson Custom Homes recently installed a grey exposed aggregate driveway using recycled sea shells at a home being built in Landfall. Exposed aggregate with broadcast sea shells gives concrete the elegance and beauty of the old south. 


The process includes broadcasting and pressing recycled sea shells into concrete when wet, then removing the top surface when the concrete flashes (water evaporates) allowing the beautiful shells to appear.

Buckets of Shells

Adding the Aggregate to the Concrete:

The most commonly used method is to seed the decorative aggregate onto the slab surface immediately after the concrete has been placed, struck off, and bull floated. This involves sprinkling the aggregate by hand or shovel uniformly onto the surface and then embedding it with a bull float until it’s completely covered by a thin layer of cement paste.

Before Shells

Exposing the Aggregate:

There are several exposure methods contractors can choose from, depending on the look desired and size of the project. Only the top of the stone is exposed while the rest remains permanently embedded in the concrete. The general rule of thumb is to remove the surface concrete to a depth no more than one-third the diameter of the aggregate particle. Brushing and washing is the oldest method and the simplest because it doesn’t require chemical retarders or special tools. You just wash away the thin layer of surface concrete covering the aggregate by spraying with water and scrubbing with a broom until the aggregate is exposed to the desired depth. The timing of the operation is critical, however, so this method is often better suited for small jobs. The work should begin as soon as the surface concrete can be removed without overexposing or dislodging the aggregate. You can test this by lightly brushing away the surface mortar in a small area with a stiff nylon-bristle broom.

Sea Shell Driveway

Choosing Decorative Aggregate:

The color palette of an exposed aggregate surface is largely determined by the type of decorative stone that’s used. Aggregate selection can also have a big impact on the total cost of the project. Expensive aggregates are not always needed to achieve impressive results. You can also use manufactured materials such as recycled colored glass.


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3 Responses to “Exposed Aggregate Driveways”

  1. drivewaysandpavingservices Says:

    I have seen a few drives like this and it really does look incredible. Abit out of place for the city but by the sea its a must!

  2. Maggie Says:

    I've seen like sea glasses, in one of my friends townhouse. Looks awesome and colorful in the eyes. My children will like it.

  3. Prestigecon Services Says:


    Thanks for sharing your valuable information with us…..