Stabilizers of road masses for the construction and repair of highways

The development of road construction began with the use of natural materials: gravel-sand mixtures, soils and rubble stone, for the construction of road coverings. This was enough for horse-drawn transport. But with the development of the automotive industry, the requirements for the quality of highways have undergone significant changes. This state of affairs made it necessary to create monolithic coverings made of organomineral and concrete mixtures for road coverings. Their components are bitumen and cement, which are very expensive components. In order to reduce the required amount of binders and increase the strength and quality of organo-mineral and cement – concrete mixtures, various impurities such as surfactants and catalysts were used. Due to the use of active admixtures, the process of reducing the amount of necessary binders was observed without reducing the quality of manufactured materials. Finally, the time has come when the consumption of active binder for the production of asphalt and cement-concrete mixtures has been reduced to a minimum, while maintaining the quality and strength conditions. 

A similar situation occurred in the technology of soil use. Currently, it is known that it is advisable to use appropriate active admixtures - stabilizers to strengthen them. [1-8] 

In connection with the achievement of minimum costs of both bitumen and cement in the manufacture of asphalt and cement-concrete mixtures, due to the targeted use of various active impurities and optimization of technological processes, the question arises: can active impurities not be self-sufficient components in terms of increasing the strength and stability of both road construction materials and soils? 

Experimental studies have shown that the treatment of mineral materials, and, above all, soils, with an aqueous solution of various active impurities leads to the formation of strong structures, both soils and mineral materials, especially in cases where mineral mixtures and soils have at least 15% by weight of the fine particle fraction. On this basis, manufacturers of various substances that activate the structure-forming process called them stabilizers of mineral mixtures and soils. 

Each specific stabilizer has its own individual, often unusual, name. So, the American EN-1 and SPP-produced in the Republic of South Africa and Russia are called Roadbond, which translates as "road shackles", RRP - 235 Spesial produced in Germany, translated as "royal special road product", Terraston - produced in Germany translates as "strong (hard) stone". Dorzin-produced in Ukraine - " road enzyme”. Dorzin is superior in its properties to all other stabilizers known to us [1-8]. 

Stabilizers are a very wide class of substances of different composition and origin, which in small doses have a positive effect on the formation of the properties of road construction materials, both by activating physical and chemical processes and by optimizing technological processes. These substances can be used at almost all technological stages of road construction, starting from the construction of the roadbed and ending with the construction of hard surfaces, artificial engineering structures and road construction. 

Stabilizers can be of different origin, they differ in properties, but all of them are united by the fact that they increase strength, moisture resistance and frost resistance. Stabilizers can be considered as "vitamins" that stimulate not only physical and chemical processes as catalysts, but also improve the quality and efficiency of mechanical and technological processes. 

The experience of using road mass stabilizers has shown that most soils treated only with a stabilizer are not water-resistant and do not withstand standard tests according to the standards in force in Ukraine. Experimental work has also shown that stabilizers combined with low doses of inorganic binders make it possible to produce strong and water-resistant compositions that meet current standards. 

The use of stabilizers to improve the condition and quality of soils without the use of inorganic binders such as cement or lime is advisable only if the treated soil is not actively affected by water. The area of use of soils improved only by stabilizers in connection with the above is rationally limited to areas with the first type of terrain for moisture, as well as mainly the third road climate zone of Ukraine. Soils with a stabilizer and binders, such as cement, can be used in almost any climatic zones with any type of terrain for moisture. 

The list of stabilizers known in Ukraine that were used in experimental studies is given in the Table. Comparative data are shown in Fig.1. The table. 

The results of experimental studies made it possible to draw the following conclusions: 

* Soil stabilizers are characterized as multicomponent systems that have a predominantly acidic environment, have the properties of surfactants, and usually include superplasticizers, hydrophobizers, and complex organic compounds that include ester groups and ionogenic complexes. 

* Stabilizers are recommended to be used in the form of a diluted water solution. As a result of dissolving the stabilizer in water, the latter is activated by ionization (H+, OH, H3O). The stabilizer solution actively affects the condition, first of all, of clay and colloidal soil particles. It changes the charge of clay-colloidal particles due to the energetic exchange of electric charges between ionized water and soil particles, which is confirmed by studies of the pH of the stabilizer solution medium and the pH of the water extract of the soil. By exchanging charges with ionized water, natural connections with capillary and film water are disrupted between ground particles. It is easily separated from soil particles, thereby creating favorable conditions for high compaction of the soil mixture during compression. * In addition to the exchange between the electric charges of the stabilizer water solution and ground particles, an ion exchange process occurs between the stabilizer components and the absorbing complex of the clay-colloidal fraction, which is indicated by a decrease in the optimal tamping humidity. 

The multivalent stabilizer and soil ions released as a result of recharge of soil particles penetrate the absorbing complex of the clay-colloidal fraction and squeeze out the monovalent Li, Na, K, and H ions. This process leads to coagulation of clay and colloidal particles, and as a result, to changes in the granulometry and structure of the soil. That is, there is an artificial formation of particles (aggregates) in the ground, such as sand. Soil from the category of clay or loamy tends to move to the category of light loamy or sandy loam. The optimal tamping humidity of such soil is noticeably reduced and this increases the maximum density of the standard seal. This leads to an increase in the load-bearing properties of the soil. 

* Stabilizers also play the role of a plasticizing admixture, which makes it possible to achieve higher density values at lower optimal humidity [1.3]. 

* Stabilizers help to increase soil density and strength in the non-water-saturated state, but do not provide high water resistance for most soils, which requires the introduction of special measures that eliminate sources of active moistening of the roadbed or additives to the soil, such as cement [1]. 

* When using stabilizers, a seal is achieved 1.1-1.2 times greater than when sealing without a stabilizer. 

* Stabilizers show positive results from their joint use with traditional binders, which is confirmed by practical results during the overhaul of asphalt concrete surfaces using cold recycling technology, for example, on the Kharkiv-Sumy road. EN-1 stabilizer, cement, 3% clay soil and milling chips of old asphalt pavement were used there. 

* Some stabilizers allow you to get compositions that are not inferior to cement concrete. 

For the use of EN-1 and Perma-Zyme 11x stabilizers in the road construction industry of Ukraine, the State Research Institute has developed technical specifications for” Organo-mineral mixtures and soils treated with cement and EN-1 stabilizer "TU V. 2. 7. 3450778. 097-98 and for" Organo-mineral soils and mixtures treated with Perma-Zyme 11x enzyme and cement” TU in 2.7-45.1-3450778-196-201. 

Dnipro Association-K LLC took four years to synthesize a replicant (analog) of the industrial enzyme stabilizer Perma-Zyme 11x produced in the USA. Then an improved version of the drug called Dorzin was created, which has been produced in Ukraine since 2006. In terms of efficiency, it surpasses all known stabilizers in Ukraine (Fig. 1), is safe and technologically advanced in use. It is an enzyme preparation with catalytic properties. For the construction of 1 km of hard surface with a width of 8 meters, a thickness of 0.15 m. it requires only 37 liters. The price of a solid road surface is 4-8 times lower than a surface made in the traditional way with the same load-bearing capacity. Dorzin is widely used in different countries. Thus, in Kazakhstan, Dorzin is used in the construction of a Category I highway (Figs.2, 3) from the capital of the Kazakh Republic Astana to Petropavlovsk (1000 km) through the resort town of Borovoe (300 km section). In 2007, 50 km of the highway will be built. The technology is so well developed by Kazakh road builders that in July 2007 they plan to reach the capacity of 1 km of finished road surface per day! The use of Dorzin in the construction of a ring road near Astana is considered. 

Dorzin is used in Russia, Haiti, Santa Lucia, even in the USA-in the homeland of Perma-Zyme 11x, in the state of Florida they are building a highway using Dorzin, from where the soil for research is supplied to Kiev, where soil mixtures are developed and construction recommendations are issued. Customers from Jordan, Saudi Arabia, Ghana and others expressed their intentions to build roads using Dorzin. 

In Ukraine, stabilizers are not used. Even Dorzin is used very sparsely in its homeland. As one high - ranking road manager said: "Good technology, but the volume is not the same.....". What a pity! 

Conclusions: 

1. It is advisable to use road mass and soil stabilizers in combination with cement in the construction of any road surface components, especially for entrances to villages and farms. 

2. It is economically efficient and technically expedient to use stabilizers in the repair and reconstruction of road surfaces using cold reysackling technology. 

3. In order to widely use the domestic stabilizer Dorzin, which has received recognition in different countries, it is necessary to develop recommendations on the use of Dorzin in the road construction industry of Ukraine. 

List of links:

1. Candidate of Technical Sciences V. G. Yumashev, Candidate of Technical Sciences S. G. Fursov Candidate of Technical Sciences V. S. Isiev (Soyuzdornam) " Possibilities of using stabilizers offered by foreign companies” Highways No. 3-4, 1995. 

2. Study of the possibility of obtaining a surface-active stabilizer of clays and clay soils of the RRP stabilizer (FRG) from available sources of raw materials. Petrochemistry Department of the Institute of Petrochemistry of the Academy of Sciences of the Ukrainian SSR topic code 9.11-Kiev, 1985 

3. V. V. Epishkin. Use of soil stabilizers. Highways No. 7-8, 1995. 

4. Chemical stabilization of soil compaction under low-cost construction conditions. Roadbond SPP TRADEFI INTERNATIONAL LIMITED. Republik of South Africa. 

5. Production technology robot using soil stabilizers "Roadbond" in road construction. Dorozhnye tekhnologii Company, Moscow, 1996. 

6. Soils, mixtures of soil-crushed stone and sand-gravel, treated with a soil stabilizer "Roadbond" for road construction, technical specifications TU 5732-000-40035037-96, Russia. 

7. Roadbond. Prospects of application in Russia. Highways No. 9, 1997. 

8. Roadbond EN-1 “Patented Roudbase Stabilizer. Tested in the Jab. Proven in the Field. Manufactured by: c.s.s Technology”, the. P.O. Box 1995. 

Abstract to the article: 

Samoylenko Yu. N. (Dnipro Association-K LLC), Sasko M. F. (GosdorNII) 

Road mass stabilizers for road construction and repair. 

The article presents in a general form information that reproduces the source of the emergence of such a concept as road mass and soil stabilizers. A table of the list of stabilizers that were used in experimental experiments is given. The positive effects of stabilizers on the formation of the structure of organo-mineral mixtures and soils treated with stabilizers are considered. Data on the strength of crushed asphalt concrete treated with various stabilizers and reinforced with cement are presented. 

Authors: 

Yuriy N. Samoylenko-General Director of Dnipro Association-K LLC, Hero of Socialist Labor. 

Sasko Nikolay Fedorovich-Candidate of Technical Sciences, leading researcher of GosdorNII.