We made 150 concrete ties using this wall forming tie instead of rebar. The cost was in the range of $.16 per. This might be an alternative to rebar. But it is possible that a tie could be cracked during a derailment of a heavy locomotive. The tie should be able to remain in service, if it does not flex. The reinforcing needs to be able to resist the pull out forces applied to it if the tie would flex as a load moves over it. We also had to consider that if a tie had a hair line crack in it, how long would it be before this kind of reinforcing would start to rust from water intrusion at the crack. Reinforcing of this type could rust through itself is a few years. A #3 or #4 rebar with deformations could rust for many more years thus the tie life would be much greater. So we have installed those 150 ties mixed in with the rest. Time will tell if this type of reinforcing is as good as regular rebar.
Admixtures to reduce water intrusion etc..
We do not think concrete ties will conduct electricity more or less than water logged treated wood ties. But if it is felt that water intrusion into the concrete tie might effect track sensed signaling or life of the concrete tie, then there are a few things that can be done to the concrete during fabrication and afterwards.
One: There are concrete surface sealers in use on highway bridges and parking garages that are
easy to work with. There is a two-part polysulfied epoxy that works exceptionally well.
Mark-124 made by Poly-Carb in Ohio is one that comes to mind. Each tie could be
momentarily dipped in this solution or sprayed on prior to installation. This solution
aborbs up to 1/4" into the concrete for permanent protection. This solution will make
the ties glossy looking for a year or two until the UV light reduces it to transparent. If
a tie gets cracked there will be some water intrusion throught the crack into the tie. The draw
back is this solution is sticky and messy.
There are other products such as Degusa BSM-40VOC and Hydrozo 20 which are even
easier to work with becasue they are single part products known as "Clear Proprietary"
Two: "Micro Silica" can be added to the concrete mix when being batched and fabricating ties.
This product is also in widespread use around the country in highway bridges and parking
structures. Since this product is mixed into the concrete itself it is a monolithic part of the
tie and cracking of a tie is not an issue for water intrusion.
Three: Liquid Latex can be added during the mixing or batching of the concrete when fabricating ties.
"Latex R" made by Sika products is available at most contractor supplies. This has the same
sealing properties as Micro Silica, but is probably cheaper and easier to use.
Four: If conductivty of signal electricity is the only concern then the use of a synthetic tie plate
instead of metal might be the answer. Since the plastic insert method is being used for
the screws they are already insulated from the tie and would not be an issue.