Concrete is
such a versatile material that it is very extensively used to build many
structures, whether they are for residences, commercial properties, factories,
bridges, dams, roads or any structure that requires a durable and strong
material. This makes the strength of the concrete being used very vital to
ensure the safety of structures.
Most
engineers prefer the concrete strength testing during the production stage. The mix of
the concrete is decided by earlier testing of the various ingredients that will
be used to make the concrete. Designing the concrete mix which will give the
weights or volumes of the various materials, like aggregates and cement is done
on an empirical basis. These mixes are then made in the laboratory where the
desired strength and density of the concrete is then tested. The accepted
standards required by the designers, allow this concrete mix to be then
suggested to the engineers carrying out the construction. It is then a
responsibility of the construction engineers to ensure that the concrete that
is manufactured and poured reaches the required strength and density as
required by the laboratory and designers.
Normal
construction procedures require that samples of the concrete being used is
poured into molds to form blocks that can be used to test the strength of the
concrete that has been poured into the structure. Concrete gathers strength
over time and standards have been set that requires certain strengths to be
developed by the concrete over periods of 3, 7 and 28 days.
The weight
of each block is then taken to arrive at the density of the concrete. The block
is then subjected to compressive stresses in testing machines to arrive at its
strength. This strength is the one obtained when the block is tested to
destruction. A number of blocks are taken for each batch of concrete, while
tabs are also kept on where this particular batch has been used in the
structure. These strengths of all the tested blocks and their densities are
noted. They are required to be as per the strengths suggested by laboratory
recommendations.
At times,
when the tests show results below what is required, engineers may prefer to go
in for other non destructive tests to establish the strength and density of the
concrete. There are various methods like rebound hammers, and ultrasonic
testing that are in wide use. In very rare cases, quality control engineers may
insist on actual load testing of the structure by using dead weight or
hydraulic forces and checking that the deflection caused is within accepted
standards.
The mix of
the concrete is decided by earlier testing of the various ingredients that will
be used to make the concrete. Normal construction procedures require that
samples of the concrete being used is poured into molds to form blocks that can
be used to test the strength of the concrete that has been poured into the
structure. Concrete gathers strength over time and standards have been set that
requires certain strengths to be developed by the concrete over periods of 3, 7
and 28 days. At times, when the tests show results below what is required,
engineers may prefer to go in for other non destructive tests to establish the
strength and density of the concrete.
Broadbeach,
QLD
4218
Contact us: 0426 508 755
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