Вяжущие материалы – Binding materials
Цемент – – Cement
Испытание цемента (активность) – cement testing
Нормальная густота (цемент) – density of cement
Сроки схватывания (цемент) – cement setting time
Тонкость помола, содержание комков (цемент) – Fineness of Cement. Checking for lumps in cement
Определение прочности на сжатие цнипс – Determination of compressive strength
Водоотделение цемента – Water separation of cement
Определение марки цемента по образцам балочек – Determination of cement grade by samples
Определение расплыва (цемент) – – Determination of cement spreading
Изготовление образцов балочек (цемент) – Cement beam samples
Определение предела прочности при изгибе (цемент) – Determination of bending strength (cement)
Определение предела прочности при сжатии (цемент) – Determination of compressive strength (cement)
Объемно насыпная плотность (цемент) – Bulk density of cement
Определение группы цемента по эффективности пропаривания образцов балочек – Determination of the cement group by the efficiency of steaming samples of beams
Определение равномерности изменения объема цементного теста – Determination of the uniformity of the change in the volume of cement dough
Сухие смеси – Dry building mixtures
Средняя плотность растворной смеси – Mean density of the mortar mixture
Расслаиваемость растворной смеси – Delamination of the mortar mixture
Водоудерживающая способность растворной смеси – Water-holding capacity of the mortar mixture
Водоотделение (тонкодисперсные смеси) – Water separation (fine-dispersed mixture)
Зерновой состав – Grain composition
Прочность сцепления с основанием (адгезия) – Adhesion strength to the base
Определение содержания непогасившихся зерен (известь) – Determination of unhydrated grains (lime)
Определение степени дисперсности порошкообразной извести – Determination of dispersion degree of pulverized lime
Начало схватывания – Initial setting time
Подвижность смеси – Mobility of the mixture
Плотность и прочность раствора на сжатие по образцам – Density and compressive strength of dried samples
Испытания сухих растворных смесей – Dry-Mixed mortar testing
Испытание вяжущих материалов – Testing of binding materials
Испытание цемента – Cement testing:
Cements are mineral binders, which are mainly used in the manufacture of building concrete and mortars. Mineral binders are divided into: air binders (air lime, gypsum, liquid glass, etc.), hydraulic binders (hydraulic lime, Portland cement, alumina, etc.) and autoclave hardening binders (lime-ash, lime-slag, etc.). The most common cements are Portland cement and its varieties.
Why testing is important for cement?
There are many cement suppliers in the construction market. But even well-known brands are not a guarantee of quality. In our practice, there have been many cases when the data of quality certificates for pure clinker cement of the 500 d0 brand did not correspond to the actual test results. The reasons are very different – from unscrupulous suppliers (expired cement, poor-quality storage and transportation, “typos” in quality documents, etc.) to unscrupulous manufacturers (underburning of clinker, the presence of unacceptable impurities).
A partial solution to this problem is the purchase of cement directly from a proven well–known manufacturer. But not everyone can afford it, since cement plants, as a rule, sell large monthly volumes with mandatory pickup. In addition, interruptions with cement begin in the summer. The cement consumer, in order not to stop, for example, the production of concrete, is forced to “intercept” cement wherever possible, work “off the wheels”, unload cements from various plants into one jar, which is even worse. In this regard, systematic quality control of cement is necessary, especially relevant at enterprises producing their own products (concrete, mortar, dry mixes, etc.).
It is necessary to check each batch of cement (the batch number is indicated in the invoice or quality certificate), regardless of the type of transport (wagon turntable, cement truck). An accelerated method for determining the grade of cement by strength can be used. There are various methods of express assessment of the grade strength of cement, based both on determining the specific conductivity of a water-cement solution and on determining the reduction in the volume of a water-cement mixture occurring during hydration of the solution (devices of the vm-7.7 type contractometers), etc.
Dry building mixes are pre–prepared at the factory powdered mixtures for the production of mortars, mastics, adhesives, paints and other fine-grained composites. Various mineral binders (cement, gypsum, lime), chemical additives, fine mineral fillers and fibers used in conventional concretes and mortars can be used to prepare dry mixes. Currently, a wide range of dry mixtures used in the construction, reconstruction and repair of buildings and structures is being produced.
Dry mixes are used for masonry, plastering, tile work, flooring, leveling walls, ceilings. The properties of dry mixtures are characterized by indicators of the quality of dry mixtures (grain composition), ready-to-use mixtures (mobility density), and solidified solution (sample density).
