Hello, everyone.
This is Enta.
Place it behind the load-bearing plate in the ground anchor assemblyLeveling Mat...Not many people can really explain how weather-resistant this is, lol.
Because nobody cares, lol (it's the kind of thing a manufacturer would say).
"The salesperson says, 'It's made of PE (polyethylene), so it'll last 100 years,' but when you ask for details, the basis for that claim is vague."
This time, Weather Resistance of PE Materials and the Role of Carbon Black (CB) ...while I'm just messing around, reading through the official verification data lol
What Is a Leveling Mat? | That black thing that would be nice to have on the back of the pressure plate
In ground anchor construction, a layer with a thickness of approximately 20 to 100 mm is sandwiched between the natural ground and the load-bearing plate. Leveling Mat。
This is a cushioning material designed to evenly distribute prestress to the compression plate.
Our flagship products are Cross-linked polyethylene foam based on Perkatite (Sekisui Chemical Products)。
Since it’s exposed to UV rays and rain outdoors, this is a place where, without weather resistance, it would fall apart within 10 years… and that’s simply not an option.
3 Key Points
- ✅ PE is prone to degradation from ultraviolet lightHowever, this can be significantly reduced by using a CB formulation.
- ✅ A typical CB formulation is 0.5–5 wt% 1TP and 3T.(General Scope of the Industry)
- ✅ Buried PE pipes for water distribution have been verified to last 100 years.(POLITEC・Yamagata University)
UV Degradation and Limitations of Polyethylene
Polyethylene resin is The main chain is cleaved by ultraviolet light with wavelengths of 290–400 nm...and gradually becomes brittle.
If PE products are left in direct sunlight without any protective measures, they will become discolored and cracked within a few years.
What works here is Carbon Black (CB) The formulation.
CB is known as a black pigment, but in the world of civil engineering materials, "The Most Effective UV Blocker" is treated as.
That's what it said lol
Why Carbon Black Works
CB particles are Absorbs electromagnetic waves in the visible to ultraviolet spectrumIt has this property.
The mechanism is that when the particles are finely dispersed within the PE matrix, ultraviolet light is absorbed by the CB particles and converted into heat, making it difficult for the UV light to reach the main chain (C-C bonds) of the resin itself.
The blending ratio is 0.5–5 wt, 1 TP, 3 T ...is the general range.
Just remember that for outdoor PE products used in civil engineering and water supply applications, 2–3% is generally the standard choice—that should be enough to explain it if you’re asked on site.
But I don't think anyone will ask!
It's just a world of self-indulgence now, lol.
The Basis for a 100-Year Service Life | Evaluation of PE Pipes for Water Distribution
The basis for the slogan “PE = 100 Years” is,Apparently, this is a long-term durability study of polyethylene pipes used for water distribution, conducted over approximately four years by the Association for Polyethylene Water Distribution Pipe Systems (POLITEC) under the guidance of Professor Kuriyama of Yamagata University.
As a result of the verification,It has been confirmed that pipes and fittings made of PE100 material, with an SDR of 11 and a maximum operating pressure of 1 MPa, have a service life of over 100 years.
Important Note: Burial Conditions and Exposure Conditions Are Different
POLITEC's 100-year validation is based solely on underground installation conditions。
This refers to the service life in an underground environment where it is not exposed to ultraviolet rays.
I don't think it's realistic to simply apply a 100-year lifespan to protective covers for leveling mats and load-bearing plates that are partially exposed to sunlight outdoors.
To be honest,"When exposed to the elements, 'PE with CB additives' is highly likely to maintain its performance for 20 to 30 years." That's a more realistic way of putting it.
And, as expected, there aren't any further experimental results.
In fact, even with the CB configuration, if you press down on the old adjustment mat from the side with your finger...
Applying This Concept to Leveling Mats
The verification data for water pipes does not directly determine the service life of the leveling mats.
However,Weather Resistance of PE+CB Blends as a Material Since they are materials from the same family, they can serve as a reference to some extent.
According to the manufacturer's track record, Perkatite (cross-linked PE foam) Over 20 years of outdoor useIt says, “There is...,” but the reality is...
I’ve also seen several areas at sites I worked on more than 10 years ago where, upon visual inspection, I found no significant signs of deterioration.
But I didn't actually touch it with my fingers (since it's up high, lol).
When explaining to the client on-site,
I think we can conclude that the service life is probably around 20 years.
It's hard to say, since there are such significant differences depending on the environment.
That said, I think the parts that are compressed due to tension and pressure are actually even more likely to be fine.
I looked into this last time as well, but once again, the results were inconclusive and ambiguous.
Well, what the manufacturer says isn't always the whole story, and it isn't necessarily accurate either.
But from a bureaucratic standpoint, it basically means that if the manufacturer says so, it’s fine—as long as it’s clear who’s taking responsibility, right?
See you later.
