Why thermal insulation and waterproofing are necessary

Much has been said and written about thermal insulation and waterproofing of buildings, but it is seldom mentioned that thermal insulation is also used in road construction. Why do roads need thermal insulation? Here’s the explanation: under the influence of low temperatures the road structure freezes, which subsequently causes damage to the pavement.

Road damage is promoted by a combination of the following factors: exposure to low temperatures; increased soil moisture and excessive water ingress; and the negative effects of cyclic loads on the roadbed.

As you can see, it is precisely from severe frost that we need to protect our roads. Winter heaving greatly accelerates their premature wear. This is a major problem for specialists who build roads.

Which materials are used in this field? We answer: the most modern and high-quality ones. One such material is extruded polystyrene foam (also known as Thermoplex).

Let’s figure out why the roadbed heaves. In warm weather, when temperatures are above freezing, the soil accumulates moisture. Consequently, at the first severe frosts this moisture freezes. It is clear that the volume increases due to ice formation, and the soil expands as a result. Of course, the depth of freezing will vary. Thus, the soil has increased in volume and “pulled” the pavement along with it, resulting in cracks in the surface that will grow over time up to the destruction of the road section.

For urban roads the situation is even worse, because in addition to water the soil is affected by engineering utilities.
But the problems are solvable: thermal insulation materials made of extruded polystyrene can reduce deformation from frost heave and reliably protect the pavement.

Extruded polystyrene boards create a kind of barrier against low temperatures. They effectively separate the road layer from the underlying soil. A zone of positive temperatures forms around the soil, the soil does not freeze, and consequently heaving does not occur.

This thermal insulation material is also effective in environments where low temperatures prevail continuously. There the reverse situation occurs: roads are built under those temperature conditions, and if the temperature rises, the ice begins to melt and the roadbed subsides.

Now to the characteristics of Thermoplex boards. This material has a closed-cell structure, which results in low water absorption; it also retains heat very well, has high strength, is resistant to deformation and damage, is not prone to deterioration, and will serve for a long time to preserve roads. But these qualities apply specifically to extruded polystyrene. Ordinary expanded polystyrene loses its positive properties rapidly when exposed to moisture and temperature variations.

With modern installation methods for such insulation, extruded polystyrene is used in the upper part of the roadbed, even without replacing existing layers. If you look at the traditional method of road construction, you will immediately see that it is much more costly in terms of time and money. Why? Because the traditional method requires, before road construction begins, the excavation of frost-susceptible soil, followed by backfilling the space with some inert materials. When using Thermoplex boards, the amount of construction work can be easily reduced to a minimum, which only benefits the road construction schedule.

In addition to all the advantages of Thermoplex mentioned above, there is another — very important — one: the road will be as durable as possible, because this insulator neutralizes frost-heaving forces and therefore the destructive effects. Interestingly, when thermal insulation boards are used the load on the pavement is distributed evenly, which also affects the quality of the road and its protection from damage, eliminating the need for frequent major repairs.