Hydraulic Conductivity (Water Permeability) Test
Permeability is a measure of the ability of a material to allow fluids to pass through it. In the case of unbound aggregate, it is typically used to refer to the ability of water to pass through the spaces between the individual particles in the aggregate. The permeability of unbound aggregate can be affected by a number of factors, including the size, shape, and distribution of the particles in the aggregate, as well as the degree of compaction. In general, unbound aggregate with larger particles and lower compaction will have higher permeability than aggregate with smaller particles and higher compaction.
Which permeability test do I need for aggregate?
There are several different tests that can be used to determine the permeability of aggregate, including the following:
Constant head permeability test: This test measures the rate at which water flows through a sample of aggregate under a constant head of water. Typically the test is performed in a small cell.
Horizontal permeability test: Horizontal permeability tests are used to measure the ability of a material to transmit fluids horizontally through its structure. Typically the test is performed in a large cell.
The choice of which test to use will depend on the specific requirements of your project and the properties of the aggregate that you are interested in evaluating. It may be necessary to use more than one test to get a complete understanding of the permeability characteristics of the aggregate. As a rule of thumb, the size of the test cell should reflect the particle size of the sample. Larger particles = larger test cells.