Cement mortar is a very durable material, it quickly sets and hardens in air. The beginning of its setting at a temperature of +20 degrees occurs in about three quarters of an hour. The solution must be used no later than an hour after its preparation, since otherwise it loses its strength. There are various grades of cement - it depends on its components. The solutions prepared on their basis have different compressive strengths.
How to make a cement mortar
To prepare the cement mortar, sift sand and cement through a sieve with a hole diameter of 3 mm. The ingredients are measured in bulk doses and mixed until a homogeneous consistency is obtained, and if necessary, re-sieved and water is added to the dry mixture until the desired density is obtained.
For laying pipes above the roof, a more complex cement mortar is made, consisting of a filler and two cementitious components: sand, lime paste and cement. In this case, you will need to add up to three parts of lime and up to 15 parts of sand for one part of cement.
Cement mortar is used for the preparation of concrete mixtures. Freshly laid concrete is covered with shavings or matting, dampened with plenty of water. This is especially worth doing in the first five days after laying into the formwork, for these purposes a plastic film is also used, which creates a vapor effect.
Cement Mortar: Composition
Cement mortar for construction can be purchased or made independently by mixing cement and sand in certain proportions (from 1 to 3, depending on the brand, to 1 to 6). It must be remembered that manually preparing the solution is not only tedious, but it is almost impossible to evenly distribute all components without appropriate experience. It is more practical to use a concrete mixer (mechanical or electric), which you can either purchase or rent, borrow from friends.
Very popular is the cement mortar, which is used for the device of masonry. For this, two types of solutions can be used - cement and cement-lime. Using the first type, load-bearing walls and other elements are erected, the second composition is used for some types of work (laying of internal walls), and only a small part of cement is added to it.
If the masonry mortar will be used in the winter, then anti-frost additives should be used that will not allow the mortar to freeze. And yet, at a temperature below 20 degrees below zero, it is better not to make the cement mass, since these components stop working. Using various additives, the solution can also be given the necessary plasticity and mobility. To increase the plasticity of the solution, professionals add ordinary shampoo, pouring half a liter of this ingredient into a cubic meter of cement mass. Salt as an antifrosty additive, despite numerous recommendations, should not be sprinkled to avoid efflorescence.
Concrete heat-resistant mixtures are also made from cement, which are used for the manufacture of structures of monolithic open fire centers, for fireboxes or blocks for laying furnaces. The following components and proportions are used to create fire-resistant heat-resistant solutions. If the solution will be used to create open fires, take a brand of cement of at least 400. Two parts of crushed stone consisting of red brick, two parts of quartz sand or finely ground red brick and a third of chamotte finely ground sand are added to one part of it. To create fireboxes, they take the same cement, crushed stone from bricks, ordinary and fireclay sand in a ratio of 1: 2: 2: 0.33.