Soils

Stone materials whose diameter is less than 0 / 0mm are called ‘soil’. Soil is formed by chemical decomposition or by physical and mechanical factors of various materials of the earth’s crust and deposits in the plains with layers of different thicknesses. Soils can contain or lack adhesives. The soil-based adhesives are called “heads” and the non-adhesives are “sand”. Of course there are carbonate impurities such as limestone and sulfate impurities such as limestone and iron compounds and vegetable and organic matter in the soil.

Soil Grading

Due to the abundance of soils of different sizes in the soils, soil aggregation evolves and is therefore divided into two general categories of soil with good aggregation and soil with poor aggregation. A well-grained soil is a soil that contains all the particles from the largest to the smallest. Soil with poor grading is a soil that contains the same size grains and there is not much difference between the size of the largest grains with the smallest grains, and the soil with incomplete grains (it has sequences) only in one or more intermediate grains. Not available.

In the following figure you can see the soil with different aggregates.

Tip: Compare the different aggregates. See the order in which they are deployed. You will learn how there is always a grain in the soil mass consisting of fine grains that fills the gap between two other rock grains.

Requirement of soil with high tolerance and bearing load as well as high specific gravity is required to control the weight percent of soil aggregate so that the voids in this soil are filled by subsequent fine grains and soil compacted as before.

Soil types

A) Topsoil:

The topsoil is formed by the erosion of igneous and metamorphic rocks such as feldspars, granites and gneisses, so it remains in the soil in addition to clay, sand and silt. Among the causes of clay adhesion properties are the fineness of the grains and their thickness.

The grains with a diameter of more than 2 microns are spherical and the grains are dotted together, but the grains smaller than 2 microns are needle-shaped or coiled, and their contact with the surface is similar to that of the spherical grains. , Much more and about 2 times.

Clay is also called “colloid” because of the fine grains. Clay has a high water absorption capacity, and after water absorption, its volume increases and when it is saturated with water, it no longer crosses it, so it is used to seal the roof as straw.

Clay is one of the cheapest and most commonly used adhesives for construction purposes and is, by definition, an air adhesive that is physically hardened and hardened.

The chemical formula of the clay is in the form of aluminum hydroxate, MSio2, PH2O, MAl2O2 with alkali and alkaline earth oxides. Pure clay is white and impurities change its color. For example, blue-colored clay contains FeO or vegetable soil, black or gray clay contains more or less coal. Fe2O3 red clay and yellow clay contain iron hydroxide. The specific gravity of clay is usually from 1 (loose) to 2 kg / m 3 (compact and hard).

Alluvial clays are displaced by water, wind, or in the glacier bed, and impurities are added along the path that results in discoloration. Alluvial clays, such as brick, ceramic, and refractory soil, are derived from the deposition of materials on the substrate of running water. In addition to dyes, there are other impurities in the soil, including silica sand, calcareous sand, feldspars, sulfates, iron minerals, sludge, and vegetable components, especially plant roots.

Clays are classified into three groups according to their impurities:

Thick clay

Medium clay

Low-grade clay

Naturally, low-grade clays have the least amount of impurities.

Clay is used to make specks, mortars of lime, gypsum, clay and straw.

The reason for the use of clay in plaster mortar is its cheapness and its slowdown. In mortar and lime, clay is mixed with lime and after a while calcium silicates and aluminates are formed. This compound does not require air, so the lime and mud mortar are among the blue mortars. The amount of clay sucking depends on the type of grains and their fineness.

Features and limits accepted:

Clay used in any project should be as pure and free from organic matter, plant roots and other vegetable debris as possible. The amount of sulfates in the clay in terms of SO3 should not be more than 0.5% and the amount of sodium and potassium chlorides should not be more than 1.5%. Coarse-grained rock for grain use is not conducive to proper soil aggregation, but in the case of clay grains consumed in mortar, up to 1.5% of grains are able to remain on a 2 micron sieve.

B) Chinese soil:

Pure clay is white. In the pottery industry, this soil is called Chinese soil. The color of ordinary soils is not white due to external materials such as iron oxide and graphite.

C) Mix (Dodge):

This is called soil with a mixture of fine and coarse grains and a percentage of clay.