How to Use Fiber Mesh in Exposed Aggregate Concrete

Prepare your aggregate concrete in a cement mixer by placing the material by volume, one part Portland cement, three parts sand and four parts decorative gravel into the mixer. Mix the dry materials thoroughly and then add water to the mix until you have a pourable concrete consistency about the same as oatmeal.

Add the fiber mesh to your cement mixer while still adding the water to the mix. Use 1 1/2 pounds of mesh in the mix per cubic yard of concrete that you’re creating in the mixer. Mix the concrete until the mesh is thoroughly incorporated into the concrete mixture.

Pour the mesh-reinforced concrete into the prepared concrete form, filling the form to a level that’s 1/4 inch below the form rim. Use a spade to help you spread the concrete mix throughout the form.

Drag a wooden screed bar across the surface of the concrete to level the pour, and then drag a bull float across the concrete to distribute the aggregate throughout the slab and pull moisture toward the surface. Trowel the concrete smooth to remove and then wait a few minutes for the moisture released by the float to sink back into the concrete.

Spread a layer of decorative gravel onto the top of the concrete, filling the remaining 1/4 inch of the form. Use a horizontal arcing motion with your hand when spreading the gravel to try to get as even a spread over the concrete as possible without burying the gravel into the mix. Spread it out even further by brushing the gravel over the surface of the concrete with a concrete brush.

Create a small concrete mix in a bucket consisting of one part cement to three parts sand and water. Add the water until the concrete is about the consistency of thin pancake batter. Use this thinned mix to pour over loose gravel on the surface of the concrete beneath. The cream on the surface of the concrete should hold the majority of the gravel in place though.

Run the float over the gravel to press it lightly into the concrete beneath, and to reveal any areas of the surface through which you can see the poured concrete below. Add decorative gravel to those areas, pouring the thinned concrete over it to keep it in place.

Roll the lawn roller over the surface to press the gravel deeper into the concrete. Watch for any developing ridges along the sides of the roller. If you see any, remove the roller, wait 30 minutes and attempt to roll the surface again. Continue rolling the surface in rows, until the layer of decorative gravel is lightly covered by a thin layer of the poured concrete. Allow the concrete to cure slightly until it no longer appears wet.

Brush off the thin layer of concrete from the top of the gravel with a soft broom to expose the surface of the decorative aggregate.

Use a garden hose to clean the tops of the exposed stones, brushing the wet stones once again with the broom to remove any concrete residue from their surfaces.

Cure the concrete for two to three weeks further. Spray the surface with water the first three days of curing time to keep the surface damp enough to avoid drying out as the concrete hardens.

Remove the concrete forms with a hammer and prybar. Spray the surface with concrete sealant to prevent staining, and then wait an additional 48 hours before using the exposed aggregate surface.