The use of coal ash at the base of country roads will make them monolithic

Roads in most summer cottages, cottage settlements and in any village are a sore subject. Dirt roads are annual repairs (bedding, grading). In our SNT, we make contributions every year for this work. We accept the amounts at the general meeting.

At the beginning of this season, in the chat we discussed the option of filling the roadway with asphalt chips. The material that remains after removing the old asphalt pavement with a special cutter. There are places on the outskirts of our city where a dirt road is filled with such a crumb:

I took photos on purpose. In 2019. this surface was perfect, like asphalt, but did not survive the winter, potholes formed. Moreover, the repair of such a coating is possible only using the technology of asphalt repair. Taking into account the fact that the cost of asphalt chips is more expensive than a good rock, we refused this option.

We stopped at the same rock of a small fraction. This is, so to speak, the finishing surface of a dirt road. If you fill up the road in an open field, then they usually do this: remove a layer of sod with black soil and cover the bottom layer with a large rock. The top is smaller.

Rarely, but there are cases when the top layer of a dirt road is covered with coal ash from boiler houses and thermal power plants. Somewhere the road gets better, ash cement the soil. I read that there are many such roads in Donbass. And somewhere the residents get solid cons - at least dust. Or "porridge" of ash, if the water does not leave the roadway.

Coal ash is a free material (only shipping costs for its delivery). Because it is a product of heat treatment of rocks (inorganic residues of organic combustion products), then in some of its properties it resembles cement. It is even added to cement:

But also since This is a finely dispersed material, then dust, if it enters the respiratory system, can adversely affect health. Although, dust from rubble, gravel, I think, is not better.

The response of the Ministry of Natural Resources division about coal ash. Probably due to the content of sulfur and other harmful substances. But nobody is going to fertilize the garden with coal ash. It's about the properties of ash as a binder. And if the ash is used not in the surface, topcoats, but in the base, then the road can acquire a monolithic base and will not fail.

This method has been known since Soviet times, watch a short video:

They are trying to implement the technology in some places, but not on a large scale. The road base material obtained by this technology resembles concrete. I think it's a promising technology. But how many decades it remains a prospect ...

Several years ago in Thailand I saw the process of reconstruction of the road on an unpaved base (many of the autobahns there are on reinforced concrete). After removing the asphalt, the machine passes through, removes the soil layer on the road, mixes it with cement (and maybe coal ash), and re-places it. The road is wetted and compacted with a roller. The subgrade becomes almost monolithic.

You can apply this method with us, but in an economy version: water the dirt roads with water with coal ash, and cover them with a layer of fine gravel on top. I think this method will help to repair dirt roads less often. What do you think?

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