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.
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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.
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 | 0º |
| 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 |
| – | – |
