How to build... a dirt road?

Let's not shrug our shoulders perplexedly after reading the title. After all, laying asphalt concrete is not always reasonable. For example, why spend a lot of money to build a highway to a remote farm or field camp in the field? Why disfigure the roadway of the street of a small village with asphalt, if it is possible to create a hard surface there without using, to put it mildly, bitumen that is not quite pleasant to the smell. Which, with all its environmental flaws, is also becoming more expensive every year, as a refined product… 

Of course, if you have money, you can also spend it on asphalt pavement. "Roll in" the earth with concrete for decades and "forget" the problem. But is it worth it? Why not adopt the American experience of building paved roads with improvised means? That is, from the ground. Moreover, - "junk". For example, using loam, sand clays. 

A few question marks that the reader "stumbled" over above can be annoying. But, let's hope that they also raised a counter question – how can a road be built from the ground so that it does not wash away the rain and the wheels of transport do not destroy it? 

Just make a reservation about the written words "American experience". They "appeared" to our eyes so, more for the "red word" (sorry for the pun). Because the American experience has been improved by Ukrainian specialists and is being applied in practice. At the same time, having a much lower production cost.* We are talking about the technology of using the enzyme preparation "Dorzin", synthesized by the Ukrainian enterprise LLC "Dnipro Association-K", the basis for the manufacture of which was the American technology for the production of a similar drug Perma-Zyme11X. And which is environmentally friendly. Because the drug is made from natural products. 

With the help of Dorzin, you can design a new road base and load-bearing surface using ground materials. And how it is done-we will tell you in stages. 

So, we are faced with the task of laying a road, say, 500-1000 meters long. First, we profile the base of the future road along the length and width with the arrangement of drainage. After that, the base is loosened to a depth of 16-17 cm (based on the calculation of getting a load-bearing coating in a compacted state-15 cm) using a grader or recycler (for example, the MRN-100R model). If the loosened soil is not enough, then we bring it to the required amount. If the road surface is being built for the first time, then we deliver the soil and put it along the prepared base. All loosened or imported soil is shifted into a shaft along one side of the road. Then, if necessary (as laboratory tests of the soil will tell you), we add an additive for water resistance: cement, or dolomite, or limestone rock. Mix the mass with a grader or disc cutter. And again, the mixed soil is shifted into a shaft along one side of the road. 

The next job of the grader is that it goes along the dirt shaft, grabs about 1/3 of its part, shifting it to the middle of the road. A tanker truck following the grader waters the displaced soil with an aqueous solution of the enzyme preparation. The soil treated with the preparation is shifted to the opposite side of the road in a new shaft. Then another 1/3 of the shaft and another 1/3 are also processed, shifting them to the opposite side of the road. 

The amount of water and concentration of the aqueous solution of the enzyme preparation depends on the difference between the absolute humidity of the soil mixture and its optimal tamping humidity. As a rule, the concentration of the drug in water is in the range of 1: 500-1: 1000. 37 liters of enzyme preparation are required for a road surface 1 km long, 8 m wide and 0.15 m thick. 

Of course, reading this simple technology, a purely technical question may arise about what kind of soil can be used, and in what proportion to prepare the mixture. 

We are responding. General conditions for the construction of road surfaces using an enzyme preparation when selecting a soil (or mixture) are as follows:: 

the number of plasticity of the soil should be in the range I o=1-22; 
the ground should be uniform in length, width and thickness of the coating; 
soils containing more than 2.9% humus by weight, more than 2% sulphate salts, more than 4% chloride salts, and more than 10% gypsum are not allowed for construction%; 
the composition of the soil must include at least 15% by weight of particles with a size of 0.075 mm; 
as a rule, most soils for water resistance require an additive for water resistance: cement grade 400-500, or dolomite, or limestone rock. For example, cement or dolomite is added in an amount of 3-8% by weight. 

In Ukraine, soils that are widespread everywhere are suitable for such construction: 

- sandy loams are pulverized and heavy pulverized with the plasticity number I0=1-7; 
- loams are light, dusty, and heavy with the plasticity number I0=1-17; 
- sandy clays with the plasticity number I0=17-22. 

Each soil intended for use should be tested in the laboratory with the release of samples made with a standard compaction force. If necessary, the optimal mixture is selected on its basis, providing the necessary coating strength, moisture resistance and frost resistance. 

For example, on humusized soils, mixtures with the addition of granulometric slag and cement have proven themselves well. 

As a result of the study of the soil and the selection of the mixture, the following parameters should be determined:: 

the ratio of the components of the mixture, for example: clay and sand, if there is no suitable homogeneous soil; 
type and amount of additive in the mixture for moisture resistance; 
optimal tamping humidity of the mixture with the enzyme preparation solution; 
density achieved during the coating manufacturing process; 
strength characteristics at 7 and 28 days of age in a moisture-saturated state. 

Now let's go back to the coating construction technology. Mixing the soil with a solution of the enzyme preparation and additives is repeated until the entire shaft is moved to the other side of the road. The number of passageways can be increased from 3 to 5 and depends on the power of the grader, the type of ground, and the width and thickness of the road surface. 

The number of movements of the soil shaft from one side of the road to the other, as a rule, has to be done at least 3-4 times and no more than 7-8 times. We do this for the best possible and even distribution of the enzyme preparation solution in the treated soil. The drier the soil at the beginning, the more water it needs, and therefore mixing it requires. At the same time, we note that you should avoid applying a large amount of solution in one pass, as this leads to uneven wetting, the formation of puddles and lumps. Heavy clay soils that do not absorb water well require much less water to be applied in one pass. 

After mixing, proceed to layer-by-layer rolling of the soil mixture. The rolled layer is taken by a grader to a thickness of approximately 5 cm and applied along the width of the road surface on a base previously moistened with a weak solution of the enzyme preparation (1:10000) and rolled with a roller to the density determined in laboratory conditions. Next, apply 2 and 3 layers. Ideally, there should be three layers. 

A roadside is formed and....the road is ready!!! 

* Economic benefits are derived from the cost of materials and labor required for the construction and repair of one square meter of road surface. The proposed method is more cost-effective than the existing ones. Currently, in Ukraine, the price of one square meter of road surface with a load-bearing capacity of 9 tons per axle, made using the traditional method, starts from 170 hryvnias. The price of a road surface (1 m2) with the same load-bearing capacity, made using an enzyme preparation, will be: 

with Perma-Zyme 11X – 24-31 UAH/m2; 
with Dorzin – 20.1-24.7 UAH / m2. 

If the soil is delivered to the site of road surface construction, then 100 meters of pavement with a width of 6 meters can be made in 1 hour using 1 grader, 1 roller with a vibrator and a watering machine. 

At the same time, we get significant savings: 

use of local "improvised" materials (soils) in the construction area; 
reduction of the technical means used in this process; 
reducing the number of employees; 
reducing the time required for road construction (repair).