Granite crushed stone: description and key features

Many different materials are used in construction. This article discusses crushed stone as one of the most popular construction materials. It is used for roads, foundations, concrete mixes, drainage and decorative coatings. Recently, colored crushed stone has also been used for flower beds, paths and landscape objects.

Crushed stone comes in different types and with different characteristics. This is what determines its field of application. Therefore, first we will look at the types and characteristics of this building material.

Crushed stone is divided by categories, fractions, grades and classes.

Crushed Stone Categories

Based on the amount of plate-like and needle-like grains, crushed stone may be cubical, improved or ordinary. In cubical crushed stone, the content of such grains is regulated up to 15% of the total mass of the material. In improved crushed stone it ranges from 15 to 25%, and in ordinary crushed stone from 25 to 35%. The lower this percentage, the better the crushed stone compacts and the higher its price will be.

Crushed Stone Fractions

Crushed stone fractions may be main or associated. A fraction is the largest size of a single stone. The main fractions include: 5-10 mm, 5-20 mm, 10-20 mm, 20-40 mm, 20-65 mm, 25-60 mm, and 40-70 mm. Associated fractions include: 0.1-2 mm, 0.1-5 mm, 0.1-15 mm, 0.1-20 mm, 0.1-40 mm, and 2-5 mm. Each fraction has its own characteristics, and therefore the price category of each fraction differs significantly. For example, the 5-20 mm fraction bonds well in a mixture and is therefore actively used in construction. The 0.1-5 mm fraction is called screenings. The size of such stone is so small that it resembles sand. This is the smallest fraction that can be obtained during crushing. Screenings are considered a waste material, so their cost is lower.

Strength Grades

The grade of crushed stone indicates its strength. Grades include M200, M300-600, M600-800, M800-1200, and M1200-1600. The higher the numerical indicator, the stronger the crushed stone. Each grade is used in its own area. For example, M200 is used in landscape design, M300 is used for some concrete structures, M300-600 is suitable for less loaded objects, M600 and M1000 are used in road construction, while M1200 and M1400 are used for roads with heavy loads, bridges and large reinforced concrete structures.

Material Classes

After extraction and production, samples of crushed stone are taken and laboratory tests are carried out for indicators such as radioactivity, flakiness, frost resistance and water absorption. Depending on the results obtained, the class of the tested material is determined: class 1, 2 or 3. First-class crushed stone is used for the construction of residential premises. Second-class material is used for industrial and non-residential premises, as well as roads with heavy loads within and outside populated areas. Third-class material is used for roads exclusively outside populated areas. All testing and classification of crushed stone are performed according to standards.

For landscape design, cubical crushed stone of small fractions and first class is used. It is colored with a special non-toxic pigment and is therefore safe for the environment. Colored crushed stone can be purchased in construction supermarkets or at construction sites.

As can be seen, the field of application of crushed stone is truly broad. But it is not that simple, and many nuances must be taken into account. Before ordering crushed stone, be sure to review the quality certificates for the product and determine what type of crushed stone is needed for the work.