Coarse sands with grains of various sizes and with

[zihadhosenjm40]

Mixed solutions
Mixed mortars, due to their better workability, produce masonry of greater strength than mortars containing the same amount of cement but no additives. Even to comparatively rich (i.e. containing a lot of cement) mortars, in which there are 3.5-4 volume parts of sand per one volume part of cement, it is desirable to add clay or lime paste or other dispersed additives in an amount of 10-20% of the volume of cement. Leaner mortars (containing 1 part of cement and over 4 volume parts of sand) should always be made with additives.

The general nature of the influence of dispersed additives (for example, clay dough, ground limestone, etc.) on the strength of cement mortars of different compositions is illustrated. The addition of namibia mobile database dough has approximately the same effect, since the binding properties of this dough in the presence of cement are of significant importance in the first months of hardening.

small porosity require, as a rule, a smaller quantity of additives, and sands with grains of comparatively equal sizes and small ones, having significant porosity, require a larger quantity. Sands containing clay particles require fewer additives than pure sands. The disadvantage of mixed solutions is the necessity of introducing large quantities of dispersed additives into them (from 30 to 200% of the weight of cement). The work of a number of Soviet researchers, conducted recently, has shown that workable solutions can be obtained by introducing into them, instead of dispersed additives, very small quantities of surfactants (from 0.03 to 0.2% of the weight of cement, i.e., approximately a thousand times less than lime, clay, etc.)

The general theory of the influence of surfactants on the properties of building solutions was developed by academician P. A. Rebinder. Based on this theory, a number of Soviet researchers developed new methods for improving the workability of solutions by adding various surfactants (saponified wood pitch, soap naphtha, alkaline extracts from crushed plant fibers, etc.).