*3.3.3 Abrasion resistant composite materials*

The abrasion resistant composites with high thermo-mechanical characteristics and instruments from them were developed through modification of the alkaliactivated aluminosilicate cement composition by a silicon carbide. The material of the instruments that were produced commercially in Ukraine had the following properties: compressive strength – 47–50 MPa, flexural strength – 23–25 MPa, breaking strength – 5–7 MPa, thermo-resistance – 25 heat cycles "800 °С – water".

*Genesis of Structure and Properties of the Zeolite-Like Cement Matrices of the System… DOI: http://dx.doi.org/10.5772/intechopen.97520*

#### *3.3.4 Glues for wood-based materials*

The use of the alkali-activated aluminosilicate cements as a binding agent or adhesive in the production of wood-based materials permits not only to replace toxic organic resins, but to enhance considerably fire resistance.

One more example is the use of the alkali-activated aluminosilicate cements in the production of wood-based materials (chip wood aggregate concretes and wood particle boards).

The wood particle boards have densities from 500 to 1500 kg/m<sup>3</sup> , flexural strength – 8–20 MPa, swelling – less than 1% for 24 hours, the cement content in them – up to 40% by mass of the ready product.

### *3.3.5 Binders for metallurgical industry*

High thermal resistance of the alkali-activated aluminosilicate cement-based materials allowed to develop a range of products for the needs of metallurgical industry: pipes for feeding metal melt, sieves for melt filtration, heat insulating feeders, etc. The use of these materials allows for to replace high-cost ceramics. Above all, the developed compositions for moulding and core sands to be used in the foundry permit to replace highly toxic organic adhesives. The developed materials are characteristic of high green strength (up to 0.25 MPa) and strength in a dry state – up to 7.5 MPa, required minimal strength of a moulding sand after metal is fed, high values of sand reclamation (80–90%), thus meeting the requirements applied to moulding sands.

**Intumescent fireproofing and expanded heat insulating coatings** based on the alkali-activated aluminosilicate cements have coefficient of volume increase – 15–23, compressive strength – up to 4.6 MPa, water absorption – below 10% by mass, adhesion to metal – 0.78–0.84 MPa and ceramics – 4.8–5.0 MPa. The expanded coatings are characteristic of coefficient of heat conductivity (λ)–0.041– 0.065 W/m°С. Fireproofing coatings for wood, wood-based materials and fibrereinforced boards are characteristic of resistance in an open flame (800–1000°С) for 10–20 minutes. The tests and introduction at the enterprises of Ukraine showed their efficiency in replacing traditional compositions made using organic components.

**Corrosion resistant coatings** made with using the alkali-activated aluminosilicate cements have compressive strength after hardening within a temperature range of 20–150°С – 50–110 MPa, changes in mass and volume after boiling in 2% milk acid solution – 1.5–2.0%, whereas in 1–3% solutions of sulphuric acid – 2–2.5% with a coefficient of resistance 0.85–0.97 in organic mediums and 0.7–0.78 in sulphuric acid. The use of autoclave treatment allows to produce a material, which is able to withstand exposure 5–10% concentrations of these chemicals, coefficient of resistance after attacks of organic chemicals being 0.98–1.00, of sulphuric acid – 0.8–1.0 and volume changes – 2.0–2.5%. Adhesion between the coating and concrete – 3–8 MPa. The composites with the enhanced acid resistance were used in a twolayered coating of the external lining of a sewage waters disposal canal. The coatings can be recommended for service in the solutions of sulphuric acid (with concentrations below 5%), pickling solutions and solutions of heavy metal salts.

#### *3.3.6 Glues for repairing and restoration*

A variety of the alkali-activated aluminosilicate cement-based materials for repairing and restoration needs was developed: primers and putties etc.


#### **Table 7.**

*Properties of the adhesive joints made using the alkali-activated aluminosilicate cement.*

#### *3.3.7 Inorganic adhesives*

One of the most effective application of the alkali-activated aluminosilicate cements is to use them as inorganic binders for anchoring application, for bonding together various materials: mineral fabrics, fibre-reinforced heat insulating articles and paper, concrete, brick and ceramics, wood with concrete and gypsum, for metal, expanded polystyrene, plastics etc. The adhesive joints exhibit strength in non-uniform pulling-out – 3–15 MPa, high freeze–thaw resistance (more than 100 cycles) and water resistance. Examples of the use of these adhesives are given in **Table 7**.

## *3.3.8 Acid resistant ceramic materials*

Basing on the mixed albite-orthoclase compositions of the reaction products that are used as binders and silica sand as filler, the acid resistant ceramic materials with the properties of traditional acid resistant materials based on clays and those very


#### **Table 8.**

*Comparative physico-mechanical characteristics of the acid resistant ceramic materials.*

*Genesis of Structure and Properties of the Zeolite-Like Cement Matrices of the System… DOI: http://dx.doi.org/10.5772/intechopen.97520*

close to cast basalt (**Table 8**) can be produced. A curing temperature is between 1150 and 1200°C.

Testing by boiling of the specimens in Н2SO4, НСl, and НNO3 for 700 hr. showed that with the longer duration the rate of degradation of the material tended to decrease, on the contrary to the acid resistant ceramics based on clays, the process of degradation of which in the same conditions became more intensive.

Water absorption, mechanical strength and acid resistance of the materials after storage for 12 months in Н2SO4 -solutions (98, 60, and 30% concentration), in НСl-solutions (30, 20, and 10% concentrations) and in НNO3-solutions (60, 30, and 10% concentrations) suggested to conclude that corrosion of the acid resistant materials based on the alkali-activated aluminosilicate cements tended to decrease. Long-term testing showed high resistance of these materials not only in mineral acids, but in chlor-containing air media.

### **4. Conclusions**

The zeolite-like analogies to natural aluminosilicate minerals may be synthesized in the cement matrices of the Na(K)-Al2O3-SiO2-H2O system. Hydrous zeolites are formed in this system after 80 °C, after 600°C (within a temperature interval of 600–1200°C) they transform into anhydrous zeolites. The structure formation and properties of the alkali-activated aluminosilicate cement-based materials at low temperatures may be regulated by changing a cement composition, curing conditions, type and concentration of the alkaline activator solution as well as the solution to solid ratio. A directed regulation of the low-temperature structure formation process is a key instrument allowing to obtain a wide range of special materials using various types of the alkali-activated aluminosilicate cement and curing conditions. At high temperatures, the only significant factors affecting a phase composition and properties are an initial cement composition and a curing temperature. Regulation of the high-temperature structure formation is important in order to develop heat- and fire- as well as acid resistant materials. High durability of the alkali activated cement matrix can be attributed to a synthesis of the zeolite-like analogies to natural minerals. Excellent performance properties and high durability of the alkali-activated aluminosilicate cement-based materials for high temperature uses are provided due to smooth dehydration and subsequent re-crystallisation of the hydration products into stable anhydrous aluminosilicates of alkali metals.
