Vicon

VICON Cement

VICON or high-performance cement can be made to order: from super-strong cements with rugged durability to low cost cements with up to 70% mineral additives. To use a high volume of mineral additives (sand, limestone, natural pozzolans or various industrial by-products) has an important economic and ecological impact. As a result, VICON cement is stronger, cheaper and green.

High-Performance Concrete

Following the latest advances in concrete science, a high-performance concrete has been developed and successfully applied worldwide. This highly efficient product competes in new market niches not only with conventional concrete, but also with steel, natural stone, ceramic, and construction polymers. To ensure a high level of performance a variety of chemical admixtures and mineral additives must be used in exact doses; and precise control is the key to the high performance. The latest technology used in high-performance concrete plants is becoming highly sophisticated, like a chemical or pharmaceutical process. In order to manufacture high-performance concrete most concrete batching plants need additional equipment for precise control, dispatching, dosing and batch processing.

High-Performance Cement

VICON technique using a special admixture during the cement grinding process helps significantly improve properties of ordinary cement. This approach resulted in the development of a new high-tech product: high-performance cement or VICON. VICON is versatile and is expected to be a widely used material in future construction. The main idea of VICON is the addition of a new reactive silica-based complex admixture during the grinding of the portland cement. Thus, in the case of VICON cement, the clinker is ground in a ball mill together with mineral additives, gypsum and the newly invented admixture. The resulting cement is then available for the production of the high-performance concrete using conventional equipment.

[http://www.uwm.edu/~sobolev/Vicon/Vicon_files/image002.gifVICON uses a special admixture during the cement grinding]

Effect of Complex Admixture

"The use of the specially formulated admixture provides the following effects:

• pulverization of cement clinker and mineral additives;

• formation of optimal size distribution of cement particles;

• creation of highly active amorphous structures;

• physical and chemical modification of the minerals."

Importantly, in the production of VICON the amount of clinker can be drastically reduced. Even at high volumes of mineral additives the special qualities of the admixture produce blended VICON cement that is far superior to ordinary cement. Up to 70% of the cement can be replaced by cheaper local additives: sand, limestone, natural pozzolanic or volcanic materials, fly ash, granulated blast furnace slag, broken ceramic and glass items. All these can be used as low cost indigenous mineral additives. In blended VICON cement, the use of granulated blast-furnace slag in addition to high strength also provides excellent resistance to chemical attack and high temperatures. Because of low permeability and more resistant chemical structure, the blended VICON cement should easily exceed standard requirements for a sulfate- resistant cement.

Key Ingredients

To be most effective, the pre-made complex admixture requires a reactive silica-based component. Different types of available clinker can be used in the proposed process, but the best results were achieved with high C₃S and mineralized clinkers. As a result, optimized samples of high-performance cement achieved a 28-day compressive strength of up to 95 MPa (13,775 psi). The 1-day compressive strength of VICON cement was found to be as high as 44 MPa (6,380 psi), by contrast, normal cement requires one month to reach this value. Similarly, compressive strength of VICON at 2, 3, 7 and 90 days was far higher than normal cement.

New Standard for a New Cement

Various standard procedures are in place to test and control the quality of cements. VICON cement has a radically improved set of characteristics and so requires updated testing procedures. Research results indicated that the ASTM C109 or C387 test procedures are the most appropriate. The development of a new standard would lead to a breakthrough in the application of these high-performance cements. From precisely upgraded production centers VICON can be delivered to any construction site, ready mixed or precast concrete factory in standard shipments, ensuring remarkably high quality of the final products.

Global Warming & Eco-Considerations

It is generally agreed that the production of cement clinker is expensive and ecologically damaging. Carbon dioxide, a principle gas contributing to the “greenhouse effect”, is a hazard generated by the conventional portland cement process (approximately 1 ton of carbon dioxide for every 1 ton of cement). Blended VICON cement incorporates a wide range of mineral admixtures or industrial by-products, which partly replace the cement clinker. Indeed, VICON uses about 50% less clinker than inferior cements, and so it creates less ecological damage. In this way VICON contributes to the reduction of carbon dioxide at source; it economically uses waste materials that otherwise would transported to landfill sites.

Cement Plant Expansion

The manufacture of clinker consumes the bulk of capital investment and yields a slow return. Therefore expanding an existing plant requires a proportionally high rate of investment. In the case of blended VICON cement new investments only required to upgrade the grinding complex. This can help to increase the production capacity by 30-50% due to the saving on clinker. The installation of milling and control equipment requires extra investment. The complex admixture brings an additional operational cost. At the same time there is an immediate reduction in the cost of cement because less clinker is used. The increased capacity can double revenues.

Applications and Advantages

VICON cement can be used to reliable standards of high performance and high strength for manufacturing concrete in almost all conditions, therefore extending its applications. Concrete made with VICON can be applied in high-rise buildings, pre-cast reinforced concrete structures, airport runways, bridges, marine and offshore structures, tunnels, parking decks, in shotcrete and repairing of structures, underwater concrete, and special floors and many others.

Furthermore, it could become the product of choice and specification in earthquake zones. The containment of nuclear and hazardous waste is another promising area.

"The properties of VICON cement are quite remarkable, and there are considerable savings over existing construction procedures. The most important economical benefits of VICON concrete are:"

• reduced cross-sections of structures and consequent savings;

• reduced construction cost due to less weight of structures and quick erection;

• increased life-time of structures and reduced cost of repairs.

The application of high performance cement approach is not limited to materials with high strength and extreme durability, but it also can be utilized for the engineering of composite materials with special properties, such as low thermal expansion, electrical conductivity, light-reflection and many others.

The VICON cement based concretes are characterized by:

• high workability and ability to fill complicated forms;

• low bleeding and good pumping;

• excellent adhesion to any surfaces;

• high density and hardness;

• early strength up to 44 MPa (6380 psi) in 24 hours;

• ultimate compressive strength up to 145 MPa (21,025 psi);

• high abrasion resistance;

• high thermal and fire resistance; • super impermeability to gas, vapor, water and dangerous chemicals;

• excellent resistance to corrosion and efflorescence;

• very high freeze/thaw resistance (600 cycles and more);

• high resistance to chemical attack from chlorides, nitrates, acids and sulfates.

In summary, VICON cement is a cement with superior technical performance; it can be even cheaper than normal cement and has distinct ecological advantages. Neatly, VICON cement combines technological advance at a lower cost and ecological compatibility.

References

[1] Sobolev K., Mechano-Chemical Modification of Cement with High Volumes of Blast Furnace Slag. CEMENT AND CONCRETE COMPOSITES, Vol. 27, No. 7-8, 2005, pp. 848-853. http://www.uwm.edu/~sobolev/ks-mca-cement.pdf

[2] Sobolev K. and Ferrada-Gutiérrez M., How Nanotechnology Can Change the Concrete World: Part 2. AMERICAN CERAMIC SOCIETY BULLETIN, No. 11, 2005, pp. 16-19. http://www.uwm.edu/~sobolev/SobolevP2.pdf

[3] Sobolev K., The Effect of Complex Admixtures on Cement Properties and Development of a Test Procedure for the Evaluation of High-Strength Cements. ADVANCES IN CEMENT RESEARCH, Vol. AC15, No. 2, UK, 2003, pp. 65-75. http://www.uwm.edu/~sobolev/ACR-SOBOLEV-2419.pdf

[4] Sobolev K. and Podmore C., Vicon - Una Gran Idea. CONSTRUCCIÓN Y TECNOLOGÍA, 11, 2004, pp. 52-55. http://www.uwm.edu/~sobolev/ViconGCL.pdf

[5] Sobolev K. y Hermosillo R., Desarrollo De Materiales Basados En Cementos De Alto Desempeño Utilizando El Método De Activación Mecano-Química Y Su Comportamiento Con Nano-Aditivos Y Superfluidificantes http://www.uwm.edu/~sobolev/ReporteVICON.pdf