CEMENT

[:ru]Кузнецова Т. В.[:en]Kuznetsova T. V.[:] [:ru]научный руководитель, докт. техн. наук, проф., Российский химико-технологический университет им. Д. И. Менделеева, Москва, Россия[:en]esearch adviser, Doct. Eng. Sc., Prof., Mendeleyev University of Chemical Technology of Russia, Moscow, Russia[:]

Alitinform №2 (09) 2009 г. 28-36 p.

Abstract

Utilization of mineral additives, waste and byproducts of other industries is not an innovation [1–5]. Its history is quite long. The use of natural materials, such as pozzolanes, tripoli powder, gaize and diatomite is known from the time that Portland cement was created. In Russia, production of pozzolanic cements began in 1868. As metallurgy was developing, cement industry received a possibility to use large amounts of furnace slags. As a result, cement industry was developing even faster compared with metallurgy. A lack of aforementioned additives, and also a need to build hydraulic structures, was replenished by the use of sand–and–pozzolane mixture that was added to cement in amount of 40–60%.

In 1945, after the Second World War, only 2,5 mn t of cement was manufactured in the USSR. In the following years, cement production volume increased by 23–27 mn t every five years, and reached about 140 mn t in 1990 (Table 1).

Development of mixed cements outside Russia is based on the use of various additives. In early 1970s, as signs of a fuel crisis arose, many countries set a purpose to transfer to a dry method of cement production, at which consumption of heat necessary to obtain clinker is halved. However, analysis of this direction of development showed that all the countries involved had reached the level of 800 kCal per 1 kg of clinker, and this is a limit value for today level of industrial technolo­gy. For this reason, transition to manufacturing mixed (multi–component) cement type, was made to further reduce consumption of energy. Accelerated development of this direction can be proved by the following facts: half of cement produced in numerous countries is multi–component, at that the share of pure Portland cement in France does not exceed one forth of the total production volume. The average share of additives to cement accounted for 17% in 1980, 23% in 1985 and reaches 40% today. This was promoted by introduction of a standard regulating cement production (Table 2). According to this standard, it is allowable to add up to 35% of admixtures to Portland cement, without changes in the product name.