News and Research
The original testing for AirCore was done in conjunction with a test conducted at Ridgewood Country Club in Waco, Texas under the auspices of the USGA Green Section Director, Mr. Jim Moore. The beta AirCore system was installed by AirCore’s partner, Colorado Lining International on the northern half of the test green.
The initial product has functioned well since that installation four years ago, however, since that installation, the final AirCore modular design has been implemented. This new design provides an additional 200 mil thickness in the air layer and is designed to carry water in multiple directions as the water percolates through the AirCore membrane. The 300 mil thickness assures significant airflow under the green while providing more water transmission away from the root zone than the traditional &qout;gravel&auot; called for in USGA green construction.
In the summer of 2006, AirCore retained Thomas Turf Services, Inc., of College Station, Texas to conduct specific tests on simulated green profiles using AirCore versus the standard USGA green construction. The following test parameters were established:
- Define the drainage rate through the greensmix profile.
- Determine the moisture content of the root zone sand shortly after free drainage drops.
- Define any sand migration into or through the non-woven geotextile, with special consideration given for any tendency to plug the fabric.
Columns were constructed using standard USGA green profiles as the base, two columns were constructed with the recommended AirCore profile of 12" using a greensmix matched to a specific non-woven geo-textile. One column was tested using a reduced 8" root zone.
Strictest testing parameters were used in these tests conducted by Thomas Turf Services. High head pressures and high flow rates were used to simulate worst case scenarios which would be most likely to cause particle migration into and or through the test membranes. Following three repeated measurements of the flow rate through each profile, the profiles were allowed to drain for 25 minutes after which they were sampled. Each profile was laid on its side and the sand was carefully extruded from the profile and sampled in 2 inch increments. All tests were run in triplicate.
The AirCore(F) profile is designated as we offer two distinctively different non-woven geotextile fabrics. For test purposes, we wanted to be able to distinguish between the two textiles as each has a specific use. The AirCore(F) membrane is designed for use under greens in golf course construction and is offered in 10 distinct drainage feature options, depending on the greensmix. The second AirCore geotextile is specified for use in bunkers, under tee boxes and other athletic uses including sports fields, rodeo arenas, race tracks, or any area where drainage might be a concern.
Moisture Content
The following data commentary is cited directly from the Thomas Turf Services study completed on July 25, 2006.
"The individual and average moisture contents measured in the sand samples from selected depths below the soil surface for each of the profiles tested are shown in the following Tables. In all cases, the moisture contents are lowest at the surface and the greatest at the bottom of the profiles. This is due to the reduced gravitational pull on the water as one goes deeper in the profile. The USGA 12" Profile retained an average of 4.50-16.5% moisture. It is interesting to note that the moisture contents of the AirCore 12" and the AirCore(F) 12" Profiles were consistently higher than those of the USGA 12" Profile. The AirCore 12" Profile has moisture contents ranging from 7.9 to 20.3%. This is due to the fact that in the USGA system, the gravel drainage layer actually has the ability to allow the formation of a limited number of continuous water films. Therefore, the gravitational tension of the profile is somewhat greater than the depth of the sand, but probably less than the total depth of the sand plus gravel (~16"). In the AirCore 12" and AirCore(F) 12" Profiles, the gravel layer is replaced by the composite grid. Since plastic is hydrophobic and has essentially no attraction for water, a much more discrete root zone/drain layer interface is formed. This results in the formation of a true 12' gravitational tension pulling on the water in the sand which increases the moisture content of the sand layers as compared to the USGA 12" Profile. Therefore in a profile of given depth, the AirCore and AirCore(F) Profiles will retain greater amounts of plant available moisture."
Table 2-1
Table 2-2
Table 2-3
Average Saturated Hydraulic Conductivity
The following data commentary is further cited directly from the Thomas Turf Services study completed on July 25, 2006.
"Maximum hydraulic flow rates (commonly referred to as the saturated hydraulic conductivity) through the profiles measured in inches per hour are shown in Table 1-1."
Table 1-1
Also shown in the Table 1-2 are the average flow rate and standard deviation based on all 9 measurements (3 measurements on each of 3 replications).
Table 1-2
Average saturated hydraulic conductivity values for each replicate of the four profiles tested.
Also shown are the average and standard deviations.
"The data shows no statistical difference between the USGA 12", the AirCore(F) 12" or the AirCore 12" Profiles. The AirCore 8" Profile had a significantly higher saturated hydraulic conductivity. The 8" data indicate that the saturated hydraulic conductivity is being controlled by the depth of the sand and not by the underlying materials (gravel or geocomposite grid). It should also be noted that the saturated hydraulic conductivities measured here are well above those commonly used in putting green or athletic field construction."
One additional important note. "There is a significantly reduced standard deviation in the AirCore(F) 12" Profile, leading one to believe that there will be a more consistent flow throughout the green and throughout all other turfgrass surfaces throughout the golf course, or in its entirety in the case of an athletic field."
Soil Moisture Retention
The following data commentary is cited directly from the Thomas Turf Services study completed on July 25, 2006.
"Both AirCore and AirCore(F) geotextile membranes were effective in preventing the passage of sand particles. In addition, there was no indication of any sand entrapment in the fabric(s) which would result in the clogging of the membrane."
Table 3-1