Exam Flashcards
Is the weight per unit volume of a material
Specific Weight
Is acceleration due to gravity, usually given in m/s2, and on Earth usually taken as 9.81 m/s2
standard gravity
Common symbol for specific weight
γ, the Greek letter Gamma
The specimens are dried in an oven for a specified time and temperature and then placed in a desiccator to cool.
Water absorption test
There are two basic test procedures- Method A and Method B. The more common being Method A, can be used with sheet, rod, tube and molded articles. For Method A, the specimen is weighed in air then weighed when immersed in distilled water at 23°C using a sinker and wire to hold the specimen completely submerged as required. Density and Specific Gravity are calculated.
Density and Specific Gravity ASTM D792
CHEMICAL PROPERTY EXAMPLES
Flammability
Toxicity
Acidity
Reactivity
Heat combustion
Is the mass per unit volume of a material
Density
Factors affecting water absorption
Type of plastic
Additives used
Temperature
Length of exposure
Typically measured in kg/m3
density of the material
For the water absorption test, the specimens are dried in an oven for a specified time and temperature and then placed in a desiccator to cool. Immediately upon cooling the specimens are weighed. The material is then emerged in water at agreed upon conditions, often 23°C for 24 hours or until equilibrium. Specimens are removed, patted dry with a lint free cloth, and weighed.
ASTM D570
The change of one type of matter into another type (or the inability to change)
Chemical Properties
Always produces one or more types of matter that differ from the matter present before the change
chemical change
Defined as mass per unit volume
density of the material
Is a characteristic of matter that is not associated with a change in its chemical composition
Physical Properties
Is described as the behavior of the construction element against destructive influences due to scraping, rubbing, skidding, or sliding of the object on the surface, which leads to surface erosion.
Abrasion
Is a measure of the ratio of mass of a given volume of material at 23°C to the same volume of deionized water
Specific gravity
PHYSICAL PROPERTY EXAMPLES
Density
Color
Hardness
Melting and Boiling points
Electrical Conductivities
Also known as the unit weight
- Specific Weight
General Properties of Materials
Physical Property and Chemical Property
Is defined as the amount of water absorbed by a material and is calculated as the ratio of the weight of water absorbed to the weight of the dry material.
Water Absorption
A specimen is placed with the surface to be tested at a distance of 3 in. from the nozzle. The specimen is then clamped and a shield is attached. Sand is blasted on the test surface for a period of 1 minute. This procedure is repeated on at least eight spots on the test surface. Modeling clay is then used to fill in the abrasion cavities and then leveled. The mass of the clay supply is determined before and after the cavities are filled. This mass difference can be used to calculate the volume of each abrasion cavity.
ASTM C418
Are also used for relative density
specific gravity, and less often specific weight
