Themes

What is the specific weight?

We explain what the specific weight is and what are the formulas it uses. In addition, some examples and their relationship with density.

What is the specific weight and its formula?

Specific gravity is the relationship between the weight and volume of a substance . Since the weight of an object is the extent to which the attraction of the Earth acts on it, and at the same time the volume is the surface that said object occupies, the specific weight constitutes the relationship between both properties expressed in Newtons per cubic meter (N / m 3 ), according to the International System.

The calculation of it, requires numerous other properties of the substance, such as density, mass and ordinary weight of the substance. This according to the following calculation formula, in which the specific weight is represented by the symbol gamma (γ) :

γ (specific weight) = w (ordinary weight) / V (volume of the substance), or what is the same: γ = w / V = ​​mg / V, where m is the mass of the substance and g is the acceleration of gravity (commonly considered as 9.8 m / s 2 ). From there it is concluded that: γ = pg, where p is the density of the substance.

According to the International Bureau of Weights and Measures (BIPM), however, this term is not acceptable, “weight density” should be used instead.

  1. Examples of specific weight

Some examples of different materials are:

  • Plaster: 1250 N / m 3
  • Cal: 1000 N / m 3
  • Dry sand: 1600 N / m 3
  • Wet sand: 1800 N / m 3
  • Loose cement: 1400 N / m 3
  • Concrete slabs: 2200 N / m 3
  • Poplar wood: 500 N / m 3
  • Ash Wood: 650 N / m 3
  • American pine wood: 800 N / m 3
  • Steel: 7850 N / m 3
  • Aluminum: 2700 N / m 3
  • Bronze: 8600 N / m 3
  • Lead : 11400 N / m 3
  • Zinc: 7200 N / m 3
  • Iron foundry: 7250 N / m 3
  • Water : 1000 N / m 3
  • Asphalt: 1300 N / m 3
  • Stacked paper: 1100 N / m 3
  • Slate: 2800 N / m 3
  • Tar: 1200 N / m 3
  • Granite: 2800 N / m 3

Specific gravity and density

The relationship between specific gravity and density is the same as that between the weight and mass of a substance. The density has to do with the level of accumulation of matter in an object or substance, ie, the amount of material that comprises; and since the specific weight is nothing more than the force with which the Earth attracts a unit of mass of said matter, it is evident that a substance whose particles are denser together, that is, more compact than others, will be attracted with more force by gravity than other more dispersed particles.

What is the difference between specific gravity and unit weight?

Specific weight

The specific weight of a soil is its weight per unit of volume. The term is often used to characterize the solid part (particles) of a soil.

The units of specific gravity are: [F / L 3 ].

Unit Weight

Unit weight is defined as the weight of a body per unit volume. The unit weight of the soil varies according to the water content of the soil, defined as: wet unit weight (unsaturated), saturated unit weight and dry unit weight.

The unit weight units are: [F / L3].

At this point, it is good to remember that when using a scale, it is mass, not weight, that is reported.

The weight is obtained if the mass is multiplied; due to the gravity of the place where you want to know this information.

In Geotechnical Analysis programs , such as: GEO5 , for geotechnical calculation, two values ​​are required:

  • The unit weight of the soil, in its natural state, and
  • The unit weight of the saturated soil.
The first value is used for all calculations, where the ground is not submerged. While below the water table , the unit weight of the saturated soil is used.

What is the difference between mass and weight?

The mass is the amount of matter of bodies. Mass is measured in kilograms (kg) or grams (g). The mass is measured with the balance.

The weight is the force exerted by gravity on a mass. Weight is measured in newtons (N) or kilograms force. Weight is measured with the dynamometer.

Tables of Specific Weights and Densities of Materials

Specific Weights of Metals

Metal Specific Weight
(kg / m 3 )
steel sweet 7800
Cast steel 7860
Forged steel 7860
Extra mild steel 7850
Pure aluminum 2580
Aluminum beaten 2700
Cast aluminum 2600
Antimony 6690
Argentán 8400 to 8700
White cast iron 7400
Gray cast iron 7100
Cast bismuth 9500 to 9800
Liquid bismuth 10055
Bronze (8 to 14% Sn) 7400 to 8900
Aluminum bronze 7450
Bells bronze 8810
Cannon bronze 8440 to 9230
Nickel Bronze 8850
Phosphor bronze 8800
Cadmium 8650
Calcium 1580
Cobalt 8800
Cobalt powder 9500
Cast copper 8700
Chipped copper, rolled 8920
Drawn copper 8930 to 8950
Electrolytic copper 8900
Liquid copper 8220
Cast tin 7290
Whipped tin, rolled 7300 to 7500
Liquid tin 7025
Strontium 2600
Pure iron 7840
Cupola casting 7250
Liquid cast iron 6600 to 7000
Cast brass 8400 to 8700
Drawn brass (according to% zinc) 8430 to 8730
Laminated brass 8520 to 8620
Magnesium 1740
Manganese 7400
Mercury (at 0º) 13,600
White metal (from bearings) 7100
Delta metal 8600
Cast nickel 8680
Rolled nickel 8000
Molten gold 19250
Beaten gold 15300 to 19350
Native gold 15600 to 19350
Cast silver 10420 to 10530
Beaten silver 10530
Liquid silver 9510
German silver 8400 to 8700
Platinum beaten 21400
Cast platinum 21150
Solid lead 11370
Liquid lead 10640
Potassium 870
Sodium 978
Tungsten 19100
Cast zinc 6860
Rolled zinc 7190
Liquid zinc 6480

Specific Weights of Liquids

Liquid Specific Weight
(kg / m 3 )
Creosote oil 1100
Flax oil 930
Mineral oil 900 to 930
Olive oil 920
Castor oil 970
Acetone 790
Hydrochloric acid 1050 to 1200
Nitric acid 1250 to 1500
Sulfuric acid 1800 to 1900
Water 999.97
Heavy water 1107
Ethyl alcohol 800
Coal tar 1100 to 1200
Andean 1040
Benzine 680 to 720
Gasoil 675
Gasoline 750
Kerosene 790 to 820
Mercury 13,600
Naphtha 750 to 780
Paraffin 900
Raw oil 880
Refined petroleum 800
Resins in general 1070

Wood Specific Weights

Wood class Specific Weight
(kg / m 3 )
Fir tree 600
Poplar 500
Carob tree 810
Calden 630
Mahogany 820
Chestnut 800
Cedar 750
Missionary cedar 550
Incense 920
Lapacho 1000
Walnut, Oak 800
Petiribi 650
White Pine 430
Missionary pine 510
Pino Neuquén 520
Oregon Pine 550
Spruce Pine 460
Pine Tea 600
White quebracho 910
Quebracho colorado 1280
Slavonian oak 750
Virapita 900
Viraro 920

Specific Weights of Natural Rocks and Stones

Stone Type Specific Weight
(kg / m 3 )
Sandstone 2600
Porous sandstone and porous limestone 2400
Granite, sienna, porphyry 2800
Basalt, diorite 3000
Marble, slate 2800
Compact limestone 2700
Porous limestone 2400
Roof slate 2800

Specific Weights of Artificial Stones

Stone Type Specific Weight
(kg / m 3 )
Adobe 1600
Asbestos-cement 2000
Ceramic tile 1800
Stoneware tile 1900
Hydraulic tile 2100
Concrete 2200
Solid ceramic brick 1800
Perforated ceramic brick 1400
Hollow ceramic brick 1000
Slag brick 1400
Silico-limestone brick 1900

Specific Weights of Construction Materials

Material Specific Weight
(kg / m 3 )
Internal Friction Angle
Sand 1500 30th
Pumice sand 700 35th
Lime powder 1000 25th
Lump lime 1000 45º
Rubble or brick dust 1300 35th
Cement in bags 1600
Cement powder 1200 25th
Coke ash 700 25th
Cement clinker 1500 30th
Blast Furnace Slag (granulated) 1100 25th
Blast Furnace Slag (chopped) 1500 40th
Gravel 1700 40th
Plaster and plaster 1250 25th

Specific Weights of Bulk Materials

Material Specific Weight
(kg / m 3 )
Dry land 1330
Wet land 1800
Saturated earth 2100
Dry sand 1600
Wet sand 1860
Saturated sand 2100
Gravel 1700
Dry boulders 1700
Wet boulders 2000
Split stone 1700
Cement 1400
Brick dust 900
Cast 970

Specific Weights of Combustible Materials

Fuel type Specific Weight
(kg / m 3 )
Internal Friction Angle
Brown coal briquettes (stacked) 800 30th
Brown coal briquettes (stacked) 1300
Charcoal (in pieces) 400 45º
Coal coke 500 45º
Raw coal (with mine moisture)

1000 45º
Pulverized coal 700 25th
Coal in laundry waste 1200
Coal in other forms 850 30th
Wood chips 200 45º
Chopped firewood 400 45º
Lignite 700 35th
Seated wood sawdust 250 45º
Loose wood sawdust 150 45º

Specific Weights of Storable Agricultural Products

Product Specific Weight
(kg / m 3 )
Internal Friction Angle
Oatmeal 450 30th
Sugar 750 35th
Barley 650 25th
Rye 800 35th
Green peas 800 25th
Flour 500 45º
Pressed hay 170
Jewish 750 30th
Corn 750 25th
Crushed malt 400 45º
Potatoes 750 30th
Sugar beet, dried and sliced 300 40th
Beets, turnips, carrots 750 30th
Semolina 550 30th
Wheat 750 25th

Specific Weights of Other Storable Products

Product Specific Weight
(kg / m 3 )
Internal Friction Angle
Artificial fertilizers 1200 40th
Carbide 900 30th
Caked manure 1800 45º
Loose manure 1200 45º
Fish flour 800 45º
Ice 900 30th
Iron ore 3000 40th
Pyrite 2700 45º
Roasted pyrite 1400 45º
Common salt 1200 40th

Specific Weights of Other Materials

Material Specific Weight
(kg / m 3 )
Tar 1200
Asbestos 1200
Asphalt 1300
Garbage 660
Quicklime 1150
Demolition rubble 1200
Sheet rubber 1700
Ashes 900
Blast furnace slag 800
Ice 900
Common bricks 1350 to 1600
Pressed Machine Bricks 1580
Hollow bricks 1100
Refractory bricks 1850
Vitrified bricks 1600 to 2000
Paper 1100
Board 2700
Sheet plastic 2100
Porcelain 2400
Glass 2600
Cast 970
Plaster powder 1200

Specific Weights of Types of Seating

Ashlar Specific Weight
(kg / m 3 )
Basalt 3000
Granite 2800
Compact limestone or marble 2800
Sandstone 2600
Porous sandstone or porous limestone 2400

Brick and Block Factory Specific Weights

Factory Type Specific Weight
(kg / m 3 )
Solid ceramic brick factory 1800
Perforated ceramic brick factory 1500
Hollow Ceramic Brick Factory 1200
Ceramic Silico-Calcareous Brick Factory 2000
Hollow Block Mortar Factory (Heavy) 1600
Hollow mortar block factory (light) 1300
Gypsum hollow block factory 1000

Partition Specific Weights (uncoated)

Partitions Specific Weight
(kg / m 2 )
Rasilla partition (3 cm thick) 40
Hollow brick partition (4.5 cm thick) 60
Hollow brick partition (9 cm thick) 100
Hollow brick partition (12 cm thick) 140

Specific Coating Weights (per cm of thickness)

Coating Specific Weight
(kg / m 2 )
Plaster or cement plaster twenty
Lime plaster, stucco 16
Plaster trim 12

Specific Masonry Weights

Masonry Type Specific Weight
(kg / m 3 )
Common bricks with lime mixture 1600
Common bricks with cement mix 1800
Hollow bricks with lime mixture 1300
Hollow bricks with cement mix 1500
Machine bricks with lime mix 2000
Machine bricks with cement mix 2200
Bricks pressed with lime mixture 1900
Pressed bricks with cement mix 2100
Partitions of slag, char, etc. plastered with cement 1300
Refractory bricks 2700
Marble 2500
Limestone 2300
Granite 2600
Artificial stone 2100

Specific Weights of Concretes and Concretes

Concrete Type Specific Weight
(kg / m 3 )
Made of cement, sand, pebbles, broken stone or granite pellets. Unassembled (en masse) 2300
Made of cement, sand, pebbles, broken stone or granite pellets. Armed (reinforced) 2500
Of cement, sand and brick rubble 1900
Slag 1600

Specific Weights of Mixes and Mortars

Mixtures Specific Weight
(kg / m 3 )
Cement and sand 2100
Cement, lime and sand 1900
Lime and sand 1700
Lime, sand and brick dust 1600
Cast plaster 1000

Specific Weights of Floors and Pavements

Floors and Pavements Specific Weight
(kg / m 2 )
Molten asphalt 14 (for each cm of thickness)
Cement and marble tiles 22 (for each cm of thickness)
Hydraulic or ceramic tile
(Total thickness, including filling: 3 cm.)
fifty
Hydraulic or ceramic tile
(Total thickness, including filling: 5 cm.)
80
Hydraulic or ceramic tile
(Total thickness, including filling: 7 cm.)
110
Agglomerated cork on a
2 cm platform . with batten
40
Linoleum or rubber tiles on
2 cm layer of mortar.
fifty
2 cm platform. on batten
received with plaster
30
Terrazzo on mortar
(5 cm. Total thickness)
80
Parquet on 2 cm platform. and track 40

Specific Weights of Roofs and Construction Elements

Cover Type Specific Weight
(kg / m 2 )
Simple flat roof tiles with support reinforcement 75
Double flat roof tiles with support reinforcement 95
Spanish tiles with support armor 105
English slate roof over slatted Four. Five
English slate roof on 2.5 cm thick boards 55
Zinc in 0.7 mm thick sheet metal on boards 40
0.6 mm thick sheet copper on boards 40
4mm thick unarmored glass 30
Glass shingles with support reinforcement 65
Corrugated iron sheet 10
8mm thick fiber cement corrugated sheet twenty
6mm thick fiber cement corrugated sheet fifteen

Specific weights of floors and floors

Other Cover Materials
Material Specific Weight
(kg / m 2 )
One layer of tarred cardboard 5
Two layers of tarred cardboard fifteen
Slate (1/2 view) twenty
Slate (1/3 view) 30
Corrugated fibroasphalt sheet 5
Corrugated fiber cement sheet fifteen
Zinc plate (1 to 1.2 mm thick) 10
Light curved roof tile (1.6 kg per piece) 40
Standard curved tile (2.0 kg per piece) fifty
Heavy curved tile (2.4 kg per piece) 60
Light flat tile (2.4 kg per piece) 30
Regular flat tile (3.0 kg per piece) 40
Heavy flat tile (3.6 kg per piece) fifty

Specific Ceiling Weights

Types of Ceilings Specific Weight
(kg / m 2 )
plaster with batten twenty
cement, lime and sand with expanded metal 57
plastered plaster 5

 

Leave a Reply

Your email address will not be published.

Back to top button