MASTER CONCRETE ENTERPRISE Ltd. – MB series concrete modifiers

MASTER CONCRETE ENTERPRISE Ltd.

MB series concrete modifiers

General
information

  MB series concrete modifiers of multifunctional action are powder–like composite materials on organic–mineral basis. The mineral part of modifiers is composed of microsilica or its mix with fly ash and an organic part is represented by superplasticizer or its mix with setting regulator and some other admixtures.

   In accordance with microsilica/fly ash ratio of the mineral part the modifiers are subdivided into four grades indicated as MB–01, MB–30C, MB–50C and MB–100C correspondingly. According to mineral/organic part ratio each of the four grades is subdivided into separate brands. Each of the brands is in its turn indicated as follows: MB 8–01, MB 10–01...MB 10–50C... etc. The first number index (after the letters "MB") indicates the content of superplasticizer in the product weight (%), the second one - which of the above four grades it belongs to.

  The bulk weight of MB powder is within the range of 750–800 kg/m³, the size of each granule is within the limits of 0.01–0.4 mm (Fig. 1), relative moisture content – not more than 3% [1, 2].

Figure 1
Particle Size Distribution of Various Types of MB Modifiers and their Mineral Ingredients – Microsilica and Fly Ash in Natural State

  Each granule is an aggregate of microsilica ultra fine particles or a mix of microsilica/fly ash particles uniformly covered by hardened adsorption layer composed of superplastisizer and other organic components molecules.

  The hardened adsorption layer «glues together» micro filler particles stimulating formation of granules, but at the same time, being water–soluble, stimulates the granules de–aggregation while being mixed with water in the process of concrete mixture manufacturing [3, 4].

  MB modifiers are designed for manufacturing of the High Performance Concrete including very high strength concrete which generally may be obtained only by combined application of microsilica and superplasticizer.

  However, in comparison with the required component of such concrete – microsilica, a light powder–like substance of 200 kg/m³ bulk weight (or 500 kg/m³ in compacted state) making transportation and technological problems, the modifiers are more workable and transportable and their application doesn't result in corresponding manufacturing costs increase.

  As the modifiers are compositional materials of multifunctional activity, their application improve the technological properties of concrete mixtures and, therefore, there is no need in plastisizing admixtures for their manufacturing.

  Optimal dosage of MB depends on the requirements to concrete and usually varies within the limits of 8–12 % of cement weight. It may be increased or decreased if necessary.
  MB modifiers are produced on the basis of know–how protected by patents of the Russian Federation [5, 6, 7, 36, 37, 38].

Efficiency
rate

  Efficiency of modifiers of different grades containing equal weight of superplasticizer depends on its mineral part composition, i.e. on microsilica/fly ash ratio [8, 52].

  The corresponding efficiency degree estimated according to its influence on the most important concrete properties – compressive strength, permeability, frostresistance – is shown in Fig.2.

Figure 2
Effecciency of Modifiers with Various Composition of their Mineral Part (Cement=350 kg/m³; Gas forming agent=0.5 kg/m³; W/C=0.42; Slump=16-18 сm)

  Generally it may be expressed as: MB–01 > MB–30C > MB–50C > MB–100C.

Application technology

  The application of MB in the process of concrete manufacturing may be effected in accordance with generally accepted on concrete mixing units standard reception, storage, delivery and weighting to concrete–mixers circuits, and doesn't require any special equipment [3, 4].

  MB may be stored in silos, transported to the feeding bunkers by screw conveyers or pneumatic pipelines and weighted by cement batchers (Fig. 3).
  Since MB application excludes superplasticizer use and, therefore, some technological equipment for storage, delivery and dosage of chemical admixtures, the high performance concrete manufacturing is considerably simplified.

  Technical effects

  With ordinary Portland cement type M400 or M500 according to Russian Standard and normal hard rock aggregates:

High–strength (compressive strength 60–80 MPa) and very high–strength (compressive strength exceeds 80 MPa) concrete;

Concrete with high early strength cured in normal conditions (25–40 MPa in 24 hours);

Concrete of low permeability (gas and watertightness brand – W16–W20 according to Russian Standard);

High–flow concrete mixtures (Slump = 22–24 cm) which are not subject to segregation;

Improved durability concrete (increased resistance to sulfate and chloride attacks, to action of weak acids, sea water, and to frost and temperatures up to+400°C);

  The above effects can be regulated by changing the type and the brand of the modifier applied, its dosage and composition of concrete mixtures.

Storage

  MB packed into flexible containers type Big Bag may be stored in open sites and closed storing houses. In the case of storing in open sites the time of storage is limited only by durability of the Big Bags which is 12 months due to action of ultraviolet radiation and low temperatures (below – 25°C). In the case of Big Bags storing in houses and under tents the storage time is prolonged. Storing time of MB in bulk in hermetic silos and other metallic reservoirs is unlimited [1, 2].

Terms of delivery

  MB concrete modifiers are delivered in flexible MKP containers type (Big–Bags) 750 or 1000 kg each , multi–layered 30 kg bags or in bulk in cement trucks or covered rail–road cars.

Regions of MB series modifiers deliveries in 1996–2002

Up

MASTER CONCRETE ENTERPRISE Ltd.
109428, Russia, Moscow, 2 Institutskaya, 6, k.15а,
Address for correspondence:
109428, Russia, Moscow, P/O box № 6
Tel.: (095) 171–0573, 174–7635, 174–7629, 174–7606
Fax: (095) 174–7591
Е-mail:mb@niizhb.ru; info@master-concrete.com

	Each granule is an aggregate of microsilica ultra fine particles or a mix of microsilica/fly ash particles uniformly covered by hardened adsorption layer composed of superplastisizer and other organic components molecules.
	The hardened adsorption layer «glues together» micro filler particles stimulating formation of granules, but at the same time, being water–soluble, stimulates the granules de–aggregation while being mixed with water in the process of concrete mixture manufacturing [3, 4]. MB modifiers are designed for manufacturing of the High Performance Concrete including very high strength concrete which generally may be obtained only by combined application of microsilica and superplasticizer. However, in comparison with the required component of such concrete – microsilica, a light powder–like substance of 200 kg/m³ bulk weight (or 500 kg/m³ in compacted state) making transportation and technological problems, the modifiers are more workable and transportable and their application doesn't result in corresponding manufacturing costs increase. As the modifiers are compositional materials of multifunctional activity, their application improve the technological properties of concrete mixtures and, therefore, there is no need in plastisizing admixtures for their manufacturing. Optimal dosage of MB depends on the requirements to concrete and usually varies within the limits of 8–12 % of cement weight. It may be increased or decreased if necessary. MB modifiers are produced on the basis of know–how protected by patents of the Russian Federation [5, 6, 7, 36, 37, 38].
Efficiency rate	Efficiency of modifiers of different grades containing equal weight of superplasticizer depends on its mineral part composition, i.e. on microsilica/fly ash ratio [8, 52]. The corresponding efficiency degree estimated according to its influence on the most important concrete properties – compressive strength, permeability, frostresistance – is shown in Fig.2.


Figure 1	Particle Size Distribution of Various Types of MB Modifiers and their Mineral Ingredients – Microsilica and Fly Ash in Natural State


Figure 2	Effecciency of Modifiers with Various Composition of their Mineral Part (Cement=350 kg/m³; Gas forming agent=0.5 kg/m³; W/C=0.42; Slump=16-18 сm)

	Generally it may be expressed as: MB–01 > MB–30C > MB–50C > MB–100C.
Application technology	The application of MB in the process of concrete manufacturing may be effected in accordance with generally accepted on concrete mixing units standard reception, storage, delivery and weighting to concrete–mixers circuits, and doesn't require any special equipment [3, 4].

	Improved durability concrete (increased resistance to sulfate and chloride attacks, to action of weak acids, sea water, and to frost and temperatures up to+400°C);
	The above effects can be regulated by changing the type and the brand of the modifier applied, its dosage and composition of concrete mixtures.
Storage	MB packed into flexible containers type Big Bag may be stored in open sites and closed storing houses. In the case of storing in open sites the time of storage is limited only by durability of the Big Bags which is 12 months due to action of ultraviolet radiation and low temperatures (below – 25°C). In the case of Big Bags storing in houses and under tents the storage time is prolonged. Storing time of MB in bulk in hermetic silos and other metallic reservoirs is unlimited [1, 2].
Terms of delivery	MB concrete modifiers are delivered in flexible MKP containers type (Big–Bags) 750 or 1000 kg each , multi–layered 30 kg bags or in bulk in cement trucks or covered rail–road cars.