The strength of concrete measured by tests of cores is affected by the amount and distribution of moisture in the specimen at the time of test. There is no standard procedure to condition a specimen that will ensure that, at the time of test, it will be in the identical moisture ondition as concrete in the structure.
2. Portable Hardness
Hardness is a material's resistance to
penetration.
In general, an indenter is pressed into the surface
of the material to be tested under a specific load
for a definite time interval, and a measurement is
made of the size or depth of the indentation.
3. Hardness properties
include such varied
attributes as resistance to
abrasives, resistance to
plastic deformation, high
modulus of elasticity, high
yield point, high strength,
absence of elastic
damping, brittleness or
lack of ductility.
4. Basically hardness values are arbitrary, and there
are no absolute standards for hardness
Hardness has no quantitative value, except in
terms of a given load applied in a specific,
reproducible manner and with a specified
indenter shape.
5. Some Hardness Testing Methods are :
Rockwell Hardness Test
Rockwell Superficial Hardness Test
Brinell Hardness Test
Vickers Hardness Test
Mohs Hardness Test
