Nutratherm instigated a full suite of tests relating to the stability of the proposed soil blend that has been selected for a new track.
These tests include the California Bearing Ratio (CBR) (AS 1289.61.1) and the Coefficient of Permeability (AS 12184.108.40.206).
Both tests were performed according to the relevant Australian Standard by NATA Accredited Laboratory No. 547, and the results are issued in accordance with NATA requirements.
Three samples were submitted to the laboratory:
A: Sand and topsoil material collected from turf construction sand on 21/06/06, and blended according to the mix recommended by your Consultant.
B: Turf construction sand (21/06/06) blended with Supercharge (2 mm minus grade) to meet the drainage requirements of the construction specifications
C: Turf construction sand (21/06/06) blended with Supercharge (5 mm minus grade) to meet the drainage requirements of the construction specifications
Results of Testing
California Bearing Ratio
The California Bearing Ratio is a simple penetration test has been developed to test the strength of road subgrades. It is a way of putting a figure on the inherent strength of the material making up the profile. The higher the CBR reading, the stronger the profile.
CBR @ 2.5 mm penetration
CBR @ 5.0 mm penetration
Coefficient of Permeability
This measures the rate at which water passes through the compacted profile.
metres per day
Water Absorption (%)
Degradation Factor Fine Aggregate
These results indicate:
Sample B has a CBR reading which is 20% higher than Sample A. This means that the turf construction sand Supercharge (2 mm minus) is 20 % stronger (more stable) than Sample A (specified blend).
While providing a stronger profile, Sample B has a 33% better drainage capacity.
Sample C turf construction sand Supercharge (5 mm minus) has a similar strength (stability) to Sample A but has a 67% better drainage capacity.
The Water Absorption test shows that Samples B and C hold double the water than Sample A.
The lower value of Sample A for the Degradation test indicates that individual particles in this material will break down more quickly than either Sample B or Sample C.
Comments from the geologists undertaking the tests are interesting: While all samples contain material of sedimentary beginnings mainly silica, Samples B and C also contain sharp, angular particles of basalt origin supplied in the Supercharge. Their opinion is that Sample A will never perform to the same level as the other samples because it does not contain enough shapes and the particles are too rounded.
We also know that due to the Supercharge, Samples B and C to have a significantly better (500%) nutrient retention capacity than a profile of Sample A (CEC levels of around 2.5 meq per 100 g v. around 0.5 meq. per 100 grams).
Your growing medium can be blended to give you your track greater stability, moisture holding capacity and fertility whilst delivering good drainage.
Contact Nutratherm for more details how to achieve this
Terry Farrell 0414569265
Mark Farrell 0416251025