Pine Wood: Density Kg / M3 Of Pine Board And Modulus Of Elasticity, Properties And Characteristics, Conditional Density Formula And Specific Gravity Of 1 Cubic Meter. M

2024 Author: Beatrice Philips | [email protected]. Last modified: 2024-01-18 12:09

Pine wood is a demanded building material. It is used in the construction of houses, baths; it has found its application in furniture production and shipbuilding. There are several varieties of this tree in nature, each with its own distinctive performance characteristics . Scots pine is widespread in Russia.

Characteristics and properties

Pine - a tall coniferous tree with an erect trunk reaching a height of 30-50 m and a diameter of 70-100 cm, some trees grow up to 70 m. The annual growth is 1 m. The pine tree lives 300-400 years. The color of the wood varies from light yellow to brown-orange, the sapwood is lighter than the kernel. The moisture content in the kernel corresponds to 33%, in the sapwood - 100–120%. Pine wood has resin passages.

Due to its high moisture permeability, pine tree can be easily treated with antiseptics, fire retardants and other protective impregnations. An important characteristic of wood is its resistance to cracking and warping during operation . The main technical and operational characteristics of pine are elastic modulus, specific gravity of 1 cubic meter. m, the level of natural moisture, bulk density, strength and density - depend on the type of wood and the place of its growth.

Composition and structure

Pine species grown in the north are somewhat different from their southern counterparts - it was their wood that became widespread during construction. The description of the physical and mechanical characteristics of the raw materials meets all the basic requirements for building materials: they have high strength and resistance to the action of pests.

In the middle of the trunk there is a thin core; when cut, it looks like a circle of irregular shape. This layer consists of parenchymal cells with lignified walls. Wood consists of even fibers, it includes tracheids, resin ducts and core rays. The entire trunk is vertically pierced with thin tracheids, they provide water delivery from the roots to the crown. Pine wood is devoid of thick-walled vessels.

The core of a freshly cut tree has a lower moisture content than sapwood. Its function is mainly mechanical - it is responsible for the stability of the barrel. On the cut, annual rings are clearly visible, while the later layers are darker than the young ones.

Varieties

Depending on the quality of wood, several main varieties are distinguished

• Selected pine - material of a high category. It has no shriveled and rotten knots, signs of fungus and mold damage, warping and visible non-parallelism of the edges. The presence of healthy intergrown knots is allowed.
• First grade - wood of the correct geometric shape. In comparison with the selected variety, the allowable presence of healthy knots is slightly increased, there may be an insignificant number of end cracks and roll within 20% of the entire area of the material.
• Second grade - rather cheap material, which differs by a greater inclination of the fiber than the material of the first grade, and the presence of single resin pockets. There may be small bluish spots and slight discoloration due to fungal infection. Such a board is used in the manufacture of scaffolding, lathing and formwork.
• Third grade . A slight roll is possible, a double core is allowed, and the number of resin pockets is increased to 4 units per linear meter. The presence of wormholes and a certain amount of rotten tobacco knots is allowed - their volume should not exceed 50% of the number of healthy ones. Through and reservoir cracks may be present. This wood is of poor quality, it has limited use: for the manufacture of containers, pallets and temporary sheds.
• Fourth grade … The number of wormholes increases to 6 units per linear meter, the proportion of rot - up to 10%. Sharp and dull wane, as well as warping along the edge, are allowed.
• Fifth grade - wood of the lowest quality with a large number of defects. Used primarily for fuel.

Density

Pine is classified as a medium-hard and medium-dense wood species, while it is distinguished by high strength - when the material is compressed along the fiber line, the maximum tensile strength corresponds to 440 g / cm 2. The material practically does not lend itself to bending, has a low resistance to splitting.

The density of pine wood is low, with a natural moisture content of up to 12%, it varies in the range from 500 to 520 kg / m3 . The density limit corresponds to 350–800 kg / m3. The relative density of the material, calculated using special formulas, directly depends on the place where the tree grows. So, the maximum parameter is calculated for pine growing in swampy areas as part of single plantings.

The material has high levels of water and air permeability … For pine of different species, these indicators differ. The northern tree has the best characteristics. Its annual rings are located at a distance of no more than 2 mm from each other, the wood is less loose and more dense, its shrinkage is minimal.

With regard to thermal conductivity, in this indicator, pine is in many ways ahead of metals, including aluminum, and is close to polyvinyl chloride. That is why the windows made of pine wood, in their ability to retain heat in the room, significantly surpass the blocks made of metal profiles.

Weight

The mass of one cubic meter of raw pine is approximately 890 kg, dry - 470 kg … This parameter directly depends on the level of natural humidity. It should be borne in mind that at different times of timber harvesting this indicator may differ: in the morning hours it is 20-30% higher than the average, and in the daytime it approaches the minimum mark.

Texture and color

The kernel of a freshly sawn pine has a pronounced pink tint. The main color depends on the pine species, place of growth and age. The structure of an adult tree is monotonous, it is characterized by high strength and low elasticity … Straight fibers. Experts classify pine of all types as medium-coarse wood species.

In the process of drying, the lumber acquires a reddish-brown tint, the core becomes darker. The wood of an adult tree is always darker than that of a young one.

Treatment

Thanks to resins, pine wood is not afraid of fungi, mold and insect pests. According to resin content, material of 2 types is distinguished:

• tar - with a high resin content;
• dry chip (oak) - with a reduced amount of resins.

Resinous pines are not recommended for use in joinery , since the viscous resin sticks to the tool and makes planing and sawing difficult. When processing such wood, you must first degum, for this use alcohol solutions, alkaline compounds, gasoline or acetone.

A dry chip, on the other hand, is easily cut, sawn and planed, and can be painted. For processing such material, mechanical and hand tools are used: a jointer, a plane and others. Such a tree is easily planed along the line of direction of the fibers, but across - with difficulty, in this case it is better to resort to sawing. The dry chip can be sanded and glued, any fasteners on it are held securely.

The high resin content makes the material prone to burning, therefore, before using it in construction and finishing works, such pine must be treated with fire retardants.

Stains may appear on the surface when painted. To avoid this effect, the board should be thoroughly dried beforehand, and the highest quality paints and varnishes should be used for work.

Comparison with other types of wood

Pine wood is similar to spruce, but there are much fewer knots in it. In addition, pine is distinguished by a striped structure, annual rings are clearly visible in the place of the saw cut, and the core rays, on the contrary, are almost invisible. Pine wood is as strong and dense as larch, yet light and rather soft. High resin content makes it resistant to sediments, parasites and fungi.

Pine wood is lighter than other woods. It is easier to process than cedar.

An important advantage of pine is its low cost . Due to the fact that this tree grows everywhere, transportation costs are minimized, and therefore the total cost of construction work is reduced. The pluses also include a pronounced coniferous aroma, which has a beneficial effect on the nervous, respiratory and cardiovascular systems.

Applications

Among all types of sawn timber, pine is in the greatest demand in the national economy. The reasons for this popularity are obvious: reliability and low, in comparison with hardwood, price.

As material

Pine is a valuable material that is often used in the construction of residential buildings, outbuildings and baths. Its tall, straight trunk with few knots is suitable for the production of round beams and logs. Resistance to decay and the action of parasites distinguishes the material favorably from spruce. However, for interior decoration, it is better to give preference to the latter, its resin content is lower.

The density and strength of pine wood allows it to be used for the manufacture of beams, rafters, piles, wooden supports and other frame structures . The low thermal conductivity of pine ensures that a favorable temperature background is maintained in the room. In addition, houses made of this material have a high level of sound insulation. Pine material is also used for the installation of subfloors and for interior cladding of residential premises.

Like fuel

The parameter of thermal combustion of wood corresponds to 4.4 kW • h / kg or 1700 kW • h / m 3. This makes it possible to use it as fuel - in the form of firewood for home stoves and fuel briquettes. Forestry waste from pine harvesting is widely used in power and thermal plants that use biowaste for energy generation.