Backfill, or backfilling, is aggregate that is removed from a building site as part of the construction process. Rather than simply being carted away and discarded, this aggregate is often used for some purpose that is not only practical, but also environmentally friendly. It can be used in tasks such as protecting foundations, landscaping, or filling in voids that would weaken underground structures.
Perhaps one of the most common uses of this material is to provide some protection along the base of a foundation wall. After the excavation of the building site is completed, the foundation is put into place. In order to provide the foundation wall with more support, the excavated dirt is firmly packed around the perimeter of the foundation. This effectively helps to minimize shifting and provide a more stable environment for the structure that is erected on the foundation.
A second application for backfilling is found with mining operations. When various types of ores are removed from the ground, there is a void left where the harvested veins once resided. In order to maintain the integrity of the mine and make it possible to continue expanding the underground mining operation, aggregate is used to fill those voids. This will minimize the chances of one or more chambers in the mineshaft from collapsing as the mining procedure continues.
Backfilling can also be put to good use when landscaping around a home, a new commercial building, or even when changing the lay of the land in preparation for a new section of road or highway. With this application, the material is brought in from another location and used to fill in or build up sections of the terrain. The aggregate makes it possible to even the ground surface so that the area around a newly constructed home can be landscaped with trees and various types of flora and fauna.
At the same time, the backfill can be hauled in to a relatively flat area and used to build up inclines that are necessary for the construction of the overpasses that are common on many highway systems. By packing the material tightly, the elevated sections easily accommodate the construction of a connecting bridge that allows an overpass to be erected over a bisecting road or street, effectively allowing the flow of traffic to proceed in a more efficient manner.
Backfill is also used to surround pipes that are buried beneath the surface. With this application, the filling helps to protect the pipe from damage, a function that is particularly important when the pipe carries electrical wiring or natural gas. The natural buffer of earth helps to absorb vibrations from the surface that would otherwise weaken the pipes over time, causing interruptions in utility service or creating health hazards for anyone living in the area.