If it is used to wash aggregate immersed in the surface layer of concrete, It is important, that this would occur after the cement binding, In the initial stage of hardening. Practically lensing is performed after 36-48 hours after the concrete arrangement. Earlier abrasion of cement and small aggregate from the surface of larger stones embedded in concrete may cause a violation of concrete and crushing, The more that quite hard brushes are used for this purpose; However, performing this operation too late, after a few days, requires much more effort. Cement residues found in the unevenness of the grain surface are removed very often with hydrochloric acid.
Making plates with gravel or crushed surfaces requires a lot of practice and should be entrusted to experienced employees. CDs with leaked aggregate are also made in labels. This enables better concrete to make (Mechanical compaction) and mechanization of the surface purification process (Mechanical steel brushes).
Certain artistic effects can be obtained by adding different dyes to the top layer of concrete. Inorganic dyes resistant to light and alkaline reaction are most often used. These are mainly black iron oxides, yellow or brown. You can also use yellow or green chrome oxide, white titanium and ultramarine dioxide. To obtain a dark gray or black color, soot is added to the concrete.
For the construction of garden concrete surfaces, it is recommended to use aerated concrete. This is achieved by introducing special admixtures that cause the formation of a large amount of microscopic follicles when mixing concrete. The advantage of aerated concrete is better workability associated with greater plasticity, occurring thanks to the decrease in internal friction. Such concrete is distinguished by much smaller water absorption, So they show higher water resistance. Aeration of concrete reduces mechanical strength slightly. In Poland, as aeration and up-to-aeration compounds, mixtures of resin acids with lignosulfanic compounds and surfactant compounds are used, np. Alkilofenol ether. These measures are delivered as liquid or powdered preparations under the name ABISOD.