What Is the Difference Between Rock & Gravel Fill?

Rock Fill Definition

• Rock filling itself is made of a variety of ground-up rocks such as marble, granite and small amounts of sand to help fill in the small areas that the larger rocks do not when they are administered and laid down then compressed as filling. Rock fill is typically made up of the rocks that are indigenous to the area in which it is being applied.

Rock Fill Uses

• Rock fill is often used in construction projects to provide access roads in hard-to-reach or rarely accessed destinations and areas that experience tumultuous weather and harsh winters. It is first dumped into place by large dump trucks and then grazed over using manual or machine-powered combs. Once the rock fill has been evenly applied, it's typically compressed down into the ground by using a steam roller or by driving over it with heavy construction machinery. This helps establish the solid rock-packed area as a drivable surface capable of withstanding large amounts of weights that are associated with vehicles of all kinds.

Gravel Fill Definition

• Gravel fill is typically grainier than rock fill and contains smaller pieces of rocks, sand, dirt and stones that are usually under 3 inches in size. There are several different kinds of gravel fill that are defined by the size of the crushed stones used. Gravel that's called 3-inch "minus gravel" is usually sold by the ton. Smaller, 1 1/2-inch gravel contain more crushed stones than the larger type, not exceeding 1 1/2 inches in size and are combined with sand and dirt. Recycled gravel contains a mixture of the two kinds of gravel and can be used for all kinds of applications.

Gravel Fill Uses

• Three-inch minus gravel is commonly used to fill in large areas. It's very boney and is useful for setting the base of a driveway that will be paved or covered with a finer gravel fill that's more aesthetically pleasing. Designed for filling in driveways and foot pathways is 1 1/2-inch gravel, also sold primarily by the ton. The recycled kinds of gravel are especially useful for filling in potholes, where they serve as the hard-packed base material that's covered in asphalt.