|Our Permeable Drain Rock is used extensively in Septic and other drain applications, including vineyard drainage
ditches, French drains, and wall backing applications. The porosity of the rock, as well as its light weight and ease
of placement also makes it a very desirable material for a variety of under slab applications. It is a durable, strong,
lightweight material making it very easy to handle and place.
We have taken core samples of the material from which we produce this drain rock . Core samples were taken
per ASTM C42., with the lowest breaks (average of three cores,) broke at 5953 PSI. The highest breaks
(average of three cores,) were 8183 PSI.
Normally, once a rock is fractured after crushing, the resulting crushed material will be stronger than it was before
crushing. The reason is that the weaker structures are fractured leaving only the stronger fractures in place. This
fact makes the compressive strengths of the pre-crushed rock shown above even more impressive.
As a comparison, residential concrete slabs are required to have compressive strengths from 2500 PSI to 3500
PSI, depending on the exact application. A 5000 PSI concrete structure is considered to be a very high strength
We also have completed a durability test on the drain rock, and the test shows a Durability Index of 90, Caltrans
test method 229. This test provides a measure of the relative resistance of an aggregate to producing clay-sized
fine particles in the presence of water. Caltrans specification for Class 1 or 2 permeable materials (drain rock) as
specified in Section 68-1.025 shall not be less than 40. This specification, in general, also follows AASHTO
specifications. The material is very clean, and all the fines are non plastic and washing is not normally required in
most septic applications.
We have also tested for Resistance, sulfates and chlorides. The resistance tested good to very good; sulfates were
so low that there should not be any direct adverse impacts on concrete, motor, grout, or cement. Chlorides are
also so low that there should be no significant corrosion impact on concrete steel reinforcement.
In addition to our traditional range of Permeable aggregate, we now have a Class IB Permeable (modified) spec
aggregate that has been used is a number of successful products. Click the links to learn more about this specialty
Class 1B Modified Pictures
Class IB Permeable Cut Sheet
Class IB Permeable Spec Sheet
We will be happy to provide back up documentation on any tests discussed in this publication.