The Role of Unselected Filling in Backfilling Applications

Selected filling is the aggregate materials used for the sub-base in roads and other construction projects but unselected filling is also widely used in the backfilling process. The latter is when soil is put back into a foundation or excavation trench.

Backfilling is normally done in layers. The soil lift is dependent upon the compacting equipment used. In many cases, water is added during compaction, making it easier to get a firmly compacted surface. The process entails, for instance, layers of a particular size, each with unselected filling that is debris-free. Then compaction takes place using the relevant equipment, whereafter the surface is thoroughly watered.

Water jetting is a backfill method in which mechanical compaction is not used at all. Highly pressurised water is applied at the bottom of the fill area. The method is not suitable for heavy clay soils. The water is pumped under pressure and moves the unselected filling material around. After water application, a period of drainage follows to ensure optimal compaction. Another form of backfill is that of flowable fill. In this method, a specific material with a low water-to-cement ratio is delivered as a ready-mix. The trench is covered with unselected filling (aggregate). Once this is done, a flowable fill covers the aggregate.

Base course and sub-base are types of selected filling materials. Stone is crushed to a specific size and the crushed stone forms the sub-base material for roads, paving, concretes, and more. Note that filling in the form of crushed stone is not used for the wear layer, but is perfectly suited for backfilling and base-course applications.

It is imperative to buy selected and unselected filling, sand, and other aggregate materials from a supplier that is near you to ensure quick delivery. It is also important to select a supplier that can deliver the bulk quantities required and can provide in all your aggregate material needs. You want a supplier that is known for quality materials, superb service delivery and reliable supply. We meet and exceed all these requirements. As a firm operating in Gauteng, we are able to deliver large quantities of unselected filling and sand to construction and roadwork sites around Gauteng. We have large trucks that are all well maintained to ensure reliable delivery. Clients can also rent the trucks.

Whether you need crushed stone, river or plaster sand, washed or unwashed sand and rock, or unselected filling, you can rely on us to meet your raw-material needs in Gauteng.