Subgrade
Summary
Subgrade - The subgrade is the bottom layer of the substructure on which the floor sub-base is normally laid.
Technical Information
The purpose of the subgrade is to provide the basis of the support for the sub-base and concrete floor.
The subgrade is composed of natural ground or imported fill. It is often stabilised or dynamically compacted with rollers to reduce further settlement of the soil while under working loads.
This layer should be isotropic throughout to provide uniform support to the slab, and hard and soft spots should be removed and replaced with material conforming to the surrounding soil. Tests can be carried out on the sub-grade to predict how much it will settle and how much support it will provide to the slab.
Subgrade Diagram
Related Definitions
Apron , Capping Layer , Plate Bearing Test , Ground Supported Floor , Slip MembraneResources
The Concrete Society: Technical Report 34; 5.2BS EN 14227: Unbound and Hydraulically Bound Mixtures. Specifications. Cement Bound Granular Mixtures. BSI, London. 2004.
The Highways Agency: Manual of Contract Documents for Highways Work. Volume 1, Specification for Highway Works, Series 600 & 800. The Stationary Office London. 2009.
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