Basic technical data of rubble
Rubbles are classified as stones having the dimensions of gravel, but obtained by methods of artificial crushing of natural rocks or bricks, pumice or slag of blast-furnace production. All the building materials are subject to certain requirements, since their qualities and properties determine how durable and attractive the buildings will be, how much all this beauty will cost, how much the operation of buildings and many other factors will cost in the future.
In the manufacture of fractions, the density of the rubble occupies an average position between the gravels of large and fine fractions and is about 1.6 t / m3, taking into account the free-flowing form of the material and the density is loose. Accordingly, determining the amount of material necessary for production, it is convenient to use the bulk weight of crushed stone in a dry state, called bulk. For preliminary calculations, the average value of such a bulk density of one cubic meter of material of 1.6 tons can be used.
Factors that affect the production and use of rubble
Since all varieties have a rough surface structure, they have good adhesion to cement mortars, forming a solid monolith of artificial stone, and most often these materials are used as quality aggregates. So, you can calculate the total weight of the rubble, which is necessary for the previously known volumes to be mastered and the planned ratio of materials in the produced concretes.
Since dust admixtures are not allowed in the preparation of concrete solutions in such aggregates, water is washed before use. This leads to the need to make certain tolerances with the above weight calculations. Among the main characteristics of specialists primarily indicate the flakiness of the rubble, as an indicator of the plane of the particles of the material.
The lower this figure, the better, and the higher the quality of the concrete obtained. This is explained by the maximum density of the ramming of grains. In addition, the rubble is characterized by the size of the fractions. Here, fluctuations in these dimensions determine the quality and their applicability in various construction industries. The smallest fractions from 3 to 8 mm are called Euro-ballast.
Fractions from 10 to 20 mm are considered to be the most popular and widely used crushed stone. Standard fractions can reach a size of 7 centimeters. But there is also non-standard crushed stone, and for it we allow a maximum particle size of 15 centimeters( !).
Performance characteristics of rubble
Knowing the technology of production, it is easy to guess that the strength of rubble depends on the strength of the stone material, which has become a raw material. If the rubble was made from mountain granite rocks, it has the greatest possible strength. But in this case, such rubble has a sufficiently high radioactive background.
For use in housing construction, only crushed rock of the first radioactive class can be used, with the presence of appropriate confirmatory research and laboratory certificates.
In addition to granite gravel, there are gravel, having strength indicators, inferior to granite, but with an absent radioactive background. Limestone( dolomite) rubble is also widely used in road construction, the characteristics of this type are in demand in the production of reinforced concrete products.
The strength of the material is indicated by its brand, and the higher it is, the greater the brand coefficient( from M1600 to M200).The most common are rubble M1200.But not only strength characterizes the construction material in question. An important characteristic is the frost resistance of crushed stone. This is also a normalized parameter, determined in the conditions of laboratory tests on control samples.
Here the leading role is played by the number of cycles of deep freezing and thawing of samples. And according to frost resistance, the rubble is heterogeneous: from 15 cycles to 300, for the most qualitative ones. By the way, they are mainly used in construction.
Crushed stone, obtained by processing artificial stones, is called secondary. Their wide application is explained by the significantly lower cost of production and quite acceptable characteristics for use in road construction, improvement and strengthening of soil structures, etc.