Accurate Soil Testing: Small Inclusions Make the Difference, Part 2
The Critical Use of Slurry with our WILDCAT DCP
A $38.00 jar of slurry protects your equipment and your data.
Little additions to products and procedures can make huge differences. In our last installment on the blog, we looked at how the Romans used lime clasts to create concrete with self-healing capabilities. In our case, we use polymer slurry with our WILDCAT DCP to facilitate accurate testing and data.
Polymer slurry is integral to the WILDCAT DCP testing process. Its use is not optional if the WILDCAT DCP operator wants accurate results, because:
Slurry filling the annular space surrounding the testing rods insulates the friction of the ground from those rods….and…
Slurry insures that the hammer’s energy is reaching the dynamic cone undiminished….and, for your convenience…
Slurry allows for easy retrieval of the testing rods from the ground.
Too often, we at Triggs get calls about rods stuck in the ground, and of course, the first question is “did you use slurry?” We do get answers like, “I don’t know for sure” and “we tend to just leave that out.” So, valuable equipment and time are lost, jobs are incomplete, and users are frustrated. Alternately, rods that are in contact with slurry and are removed using the post popper tend to slide for easy removal.
How using slurry affects data is less obvious to the user’s eye and experience, but data can vary tremendously without slurry use, especially under certain soil conditions (parasitic clay, etc.) Where accuracy is needed, use slurry.
In case you are new to slurry, or have not paid much attention to its use, here are the basics:
0.2 ounces of polymer powder reconstitutes in 4 gallons of water to create slurry of the right viscosity. The canister of polymer powder we sell ($38.00/16 oz) contains a scoop that allows you to easily measure out 0.2 ounces. The powder dissolves best in warm or hot water.
Once slurry is mixed (usually in the tank we sell, which has a 4 gallon capacity), it remains usable for about 4-5 days. So yes, you can premix slurry for several days work.
The WILDCAT DCP hammer rod comes equipped with a slurry hose and the slurry tank is outfitted with a coupler to connect to the hammer rod’s hose. Both are included in the purchase of the complete kit. (Both can also be purchased separately from us.) Once the hammer rod and slurry tank are connected, slurry is pumped from the tank, through the hammer rod, into the testing rods, and out through the ports in the end rod. Therefore, the annular space your testing creates is filled from the bottom, up.
Slurry that has been reconstituted with too little water will clog ports and be useless.
The first injection of slurry is made when the initial testing rod has been driven 30 cm. into the earth at the testing site. Slurry is pumped until the tester can see it at ground level. Throughout testing, additional slurry is pumped to maintain this level.
The ports of rods must be cleaned after testing to keep them open and able to deliver. We sell a wire brush for this, and also for cleaning testing rod threads.
Slurry must be used for conventional DCP testing and/or RAP testing using the WILDCAT DCP.
Slurry that has spilled (oh what a gooey mess) turns to water consistency with the addition of a little household bleach. Then, the mess can be easily swept or hosed away.
Polymer powder, when mixed with water as directed, is non-toxic and biodegradable. The powder, when dry, is sandy in texture and does not easily become airborne or cause respiratory risk. An MSDS sheet for ShorePac Polymer Slurry is available on our website. Go to the triggs website here.
If you are a WILDCAT user and you have not been using slurry, strongly consider adding its use to your current procedure. If you are a loyal slurry user, BRAVO! You are displaying the wisdom of the ancient Romans.
