What's the Best Material for Trench Drain Channels?
HDPE vs Polymer Concrete
For a while now, it seems like there is a battle of opinions fought between those vouching for HDPE and those claiming polymer concrete is the premium material choice for trench drain channels. Well, both sides are right! How can that be possible, you might ask?
In this article, we will examine properties, advantages, and disadvantages of HDPE and polymer concrete and give a final verdict on their suitability as trench drain materials.
What is HDPE?
HDPE stands for high-density polyethylene, or polyethylene high-density (PEHD), one of the most used plastics in the world. It´s a thermoplastic polymer which is produced from the monomer ethylene.
Because of its huge versatility, HDPE has become very popular. There are several reasons why HDPE is so widely used:
- It has a high strength-to-density ratio making it extremely strong but at the same time almost weightless
- It's super resistant to impact so it doesn't tear or burst easily
- It´s very malleable and can be molded easily into any shape necessary
- It´s long-lasting and can withstand various weather conditions
- It can resist corrosion, rotting, mold, insects, and many different solvents
- It can be easily recycled.
One of its purposes is to replace heavier materials in order to decrease the amounts used. Plastics, especially HDPE, produce much less waste, use much less energy, and therefore has a much lower impact on global warming.
HDPE is used in the production of almost everything – plastic bottles (milk jugs), toys, house wraps, geomembranes, etc. but most importantly corrosion-resistant piping. Due to its many desirable properties, HDPE pipes are ideal for potable and wastewater, e.g. sewage.
HDPE in Trench Drainage
The winning combination of toughness, low weight, durability, flexibility, high impact-resistance, resistance to chemicals and corrosion, cost-effectiveness contributed to HDPE´s widespread use ever since the 1950s in Europe and America.
For example, pipes made out of HDPE are so impermeable and strong that they´re used in the construction of high-pressure pipelines as well as for providing standard trenching of water and sewer mains.
The use of HDPE or modular HDPE is the most recent innovation in drainage systems and most commonly used. Drains made from HDPE are easy and cost-efficient to install, and provide great flow capacity.
What about Polymer Concrete?
Polymer concrete uses thermoplastic polymers instead of lime-type cement as a binder but they can also be produced by mixing mineral aggregates with a resin binding agent. The process is the same as with regular concrete only here polymers resin is used instead of water.
This mixture gets poured into a mold, after which curing beings. The result – a heavy and durable product.
Because of their high thermal stability and resistance to a wide array of chemicals, thermosetting resins are used as a primary component most often. Other aggregates include granite, limestone, quartz, silica, etc. which have to be high-quality, dust and debris-free, and dry to ensure increased bond strength.
Some of its many beneficial properties include:
- Good resistance against corrosion and different chemicals
- Durable – withstands freezing temperatures and thaw cycles
- Provides good adhesion
- Of lighter weight, bit less dense than regular concrete
- Has more significant tensile strength and greater compressive strength than common concrete
- Excellent mechanical and thermal properties (maximum working temperature 82°)
- Curing happens much faster.
It´s a versatile composite material that can be used both in new construction and the repair of old concrete. Due to its corrosion resistance, it´s used in swimming pools, sewer structures, drainage channels, etc.
Polymer Concrete in Trench Drainage
Before, polymer concrete did not experience wide use because it was much less cost-effective than the alternatives and was not that easily associated with traditional techniques and the time.
But more recently, progress has been made which led to cost reduction, making it a popular material for modern construction projects, combining quality and versatility. The use of polymer concrete in drainage construction saves money while guaranteeing consistency.
Because of their structural rigidity, when polymer concrete trench drains are installed properly, they can be applied in different pavement types – asphalt, concrete, brick pavers…
So how to choose between HDPE and polymer concrete trench drains?
In all honesty, it is not an easy choice to make since both HDPE, which gained popularity more recently, and the improved polymer concrete are both lauded as the best materials to be used in trench drain systems.
However, there are some differences between them, as well as in the expert opinion.
For example, for commercial grated trench systems, some believe that only polymer concrete meets the requirements. In their opinion, other materials cannot meet the compressive strength and thermal expansion properties needed for commercial and industrial use.
And yes, HDPE has poor thermal properties and a higher coefficient of thermal expansion, meaning that when the temperature drastically changes, the trench drain can separate from the concrete surrounding it.
This makes HDPE a poor choice for environments that experience extreme cold or heat. Plastic trench drains can also shatter due to impact while frozen.
As mentioned before, HDPE is lightweight, as opposed to polymer concrete, making it much easier to transport and handle.
One person can move a section of a plastic drain that is 10-foot, which is impossible for polymer concrete, which comes also comes in shorter lengths.
HDPE, more specifically smaller parts, can be shipped even by a courier service while for polymer concrete to be shipped and freight hauler and fork truck would need to be used.
Simply put, HDPE trench drains have lower production costs and are more affordable than polymer concrete.
Moreover, they offer a wide choice of grating options, colors, corner angles, in many widths, lengths, and styles.
In the short term, we can say that HDPE is less fragile. It is known for its impact-resistance – plastic doesn't break easily, right.
But HDPE is just not that withstanding in the long term. After some time, HDPE … It also has low industrial strength, even though plastics are promoted as able to withstand heavy loads.