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The white Portland cement WPC-1-500-D0 has been studied by us and consists of the following minerals, wt%: alite – 50.4; belite – 20.0; celite – 0.9; felite – 16.7; gypsum – 7.0. The four of one minerals are clinker, and the last is involved into the cement during its grinding.Using X-ray phase analysis (XRP), it has been found that alite and belite have a crystalline structure, and felite has a glassy structure. Amorphism of felite is the result of high-temperature clinker has been cooled rapidly with water. The composition of clinker contains impurity of individual ions in form (Fe3+, Na+, K+, Mg2+, Ti4+, Mn2+, Cu2+), which are involved in the structure of clinker minerals; they do not create independent connections and do not remain in a free state. Moreover, Na+, K+, Mg2+, and possibly Ti4+, Mn2+ ions are mainly concentrated in the structure of silicate minerals, while Fe3+ and other chromophores in the consistance of calcium alumino-ferrites. Because of this, the values of interplanar distances (d) are shifted towards smaller and larger numbers than the reference ones. According by this situation, clinker minerals are their solid solutions. The physical and mechanical properties of white Portland cement WPC-1-500-D0 meet the technical requirements in accordance with GOST 965-89. “White Portland cement. Technical Specifications". However, due to the high content of felite (3CaO·Al2O3) – 16.7%, independent compounds of the 3CaO·Al2O3·6H2O type can be created, which will significantly reduce the durability of materials and products made on the basis of this white Portland cement. Therefore, it is strongly recommended to check all white Portland cements entering the Republic of Kazakhstan for changes in strength, frost-resistance and corrosion resistance. |
