DRY MIXTURES

[:ru]Сивков С. П.[:en]Sivkov, S.[:] [:ru]к.т.н., доцент, зав. кафедрой, Российский химико-технологический университет им. Д. И. Менделеева, г. Москва, Россия[:en]PhD, associate professor, Head of Department, D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia[:]

[:ru]Ружицкая А.[:en]Rugitskaya A.[:] [:ru]Российский химико-технологический университет им. Д.И.Менделеева[:en]Mendeleyev University of Chemical Technology of Russia[:]

[:ru]Харди Х.[:en]Hardy H.[:] [:ru]Технический центр ООО Вакер Хеми Рус[:en]Technical Center Wacker Chemie Rus[:]

[:ru]Глушков А.[:en]Glushkov A.[:] [:ru]Технический центр ООО Вакер Хеми Рус[:en]Technical Center Wacker Chemie Rus[:]

[:ru]Фирсаев Д.[:en]Firsayev D.[:] [:ru]Технический центр ООО Вакер Хеми Рус[:en]Technical Center Wacker Chemie Rus[:]

Alitinform №6 (07) 2008 г. 71-75 p.

Abstract

The strength and stress-strain properties of cement-polymer compositions for exterior insulation and finishing systems hardened under extreme conditions, such as lowered humidity or freezing have been investigated. It has been established that fast loss of moisture by a material at the initial stages of hydration did not worsen final properties of material, if the material is repeatedly humidified. The freezing of fresh mortar and its subsequent thawing considerably decreases the strength of material. The addition of coalescent and antifreeze agents preventing formation of ice crystals in hardening material is offered to improve properties of cement-polymer compositions exposed to risk of shortterm freezing.

Cement-polymer compositions are widely used as a basic plaster in systems of buildings’ external heat-insulation. Such compositions are applied onto a surface of heat-insulating plates in a form of a 5-8 mm thick layer.

When plaster works are carried out during warm season, especially on facades exposed to sunlight, the temperature of fresh basic plaster layer may reach 50-70°С. Taking into consideration a large open surface of plaster layer, such temperature contributes to intensive water evaporation and material drying. At that, hardening of Portland cement containing in a composition stops. Under repeated humidifying, a process of cement hydration resumes, however final properties of hardened material may differ from those of a material that was hardened under normal conditions.