How To: Exposed Aggregate. Let the batch plant know that you're going to be placing exposed aggregate and they'll add pea gravel. They'll also review with you the size of the pea gravel. Coca-Cola is a very consistent and inexpensive way to get just the right sugar water ratio. Place it, float it, steel trowel, it rub it down. Just kidding on that last part. . Spray the top of the concrete with the Coca-Cola, the sugar will retard the top layer, allowing the concrete to stiffen up underneath. Th