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Kurdowski W.,Instytut Ceramiki i Materialow Budowlanych W Warszawie | Bochenek A.,Instytut Ceramiki i Materialow Budowlanych W Warszawie
Cement, Wapno, Beton | Year: 2012

Paper discusses the fundamental principles assuring concrete durability. It is principally low permeability, which is governing by low w/c ratio and high content of C-S-H gel, as a result of pozzolana addition. Also clinker with high C3A content should be avoided, however, even in this case low permeability is decisive, and good example is high resistance of Calcium Alumina Cement in different corrosion environments. The last important properties is low content of soluble alkalis. It is primarily important for inner corrosion of concrete, concerning alkali silica reaction and delayed ettringite formation. Source


Matusiewicz A.,Instytut Ceramiki i Materialow Budowlanych W Warszawie | Bochenek A.,Instytut Ceramiki i Materialow Budowlanych W Warszawie | Szelag H.,Instytut Ceramiki i Materialow Budowlanych W Warszawie | Kurdowski W.,Instytut Ceramiki i Materialow Budowlanych W Warszawie
Cement, Wapno, Beton | Year: 2011

Two clinkers were tested: one industrial with 0.0521% of Zn and second containing 0.61% Zn, produced in a small rotary kiln as well as three calcium - zinc phases: Ca6Zn3Al4O15, Ca6Zn2,8 Mg0,2Al4O15 and Ca3ZnAl4O10. It was found that in industrial kiln zinc is condensed on the surface of clinker grains, which shows that probably the inner circuit of zinc in kiln is formed. In the clinker from small rotary kiln the content of zinc was 0.61% and three calcium-zinc phases were formed: Ca6Zn3Al4O15, Ca6Zn2,8 Mg0,2Al4O15 and 2CaO•ZnO•SiO2. The reactions of calcium-zinc phases with saturated calcium hydroxide solution in water cause the liberation of zinc into the solution and the formation of basic calcium zincate as well as of two hydrated calcium aluminates: Ca2Al2O38H2O and Ca3Al2(OH)12. The heat of hydration of calcium-zinc aluminates is high, close to 200 J/g after 36 h and in the case of Ca6Zn2,8 Mg0,2Al4O15 even 340 J/g. Cement produced from the clinker with 0.61% of Zn has good properties. Source

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