Concrete is one of the main building products used in
the construction of a house. Depending on where the
concrete is used in the construction process, it can
become a very critical factor in the overall structural
strength of the house. Just because the concrete
comes premixed in the concrete truck does not mean
that the concrete is always good.
One factor to be considered when pouring concrete is
the slump. The individual from the testing company
will take a sample of concrete in order to determine
the slump. The technician will place a plate or board
on level ground. He then will place a metal cone on
top of the plate and fill the cone with concrete. He
would take a rod and move it up and down in the
concrete in order to settle the concrete throughout
the cone. After doing this, he will screed the top of
the cone off with the rod. He will then grab the cone
on the both sides and slowly remove the cone
upwards. This will allow the concrete to slump. The
rod is then placed horizontally on top of the cone and
a tape is used to measure the distance from the rod to
the top of the concrete. This distance is considered
the slump of the concrete
The lower the slump the greater the strength but the
harder the concrete is to work. The higher the slump
the lesser strength but the easier the concrete is to
work. When a structural engineer is involved, he
might specify that the concrete is to be 3000 psi with a
three to five inch slump. If this is specified, it is very
important to stay within these limits do not allow
anyone to add water to the mix on site without
permission from the individual doing the testing. If
the concrete is being pumped, there are additives that
can be added to the mix in order to allow a higher
slump but not jeopardize the strength of the concrete.
These additives can also be used in dry and windy
climates to allow a wetter mix and hopefully prevent
surface cracking due to the fast dehydration of the
concrete. If the concrete is tested, the slump might be
checked every fifty yards and the cylinders might be
taken at the same interval. Concrete cylinders are
taken and tested to verify the compressive strength
of the cured concrete. The cylinders are compressed
and broke at specified intervals. A cylinder broke
after 28 days should break at the designed strength or
greater.
the construction of a house. Depending on where the
concrete is used in the construction process, it can
become a very critical factor in the overall structural
strength of the house. Just because the concrete
comes premixed in the concrete truck does not mean
that the concrete is always good.
One factor to be considered when pouring concrete is
the slump. The individual from the testing company
will take a sample of concrete in order to determine
the slump. The technician will place a plate or board
on level ground. He then will place a metal cone on
top of the plate and fill the cone with concrete. He
would take a rod and move it up and down in the
concrete in order to settle the concrete throughout
the cone. After doing this, he will screed the top of
the cone off with the rod. He will then grab the cone
on the both sides and slowly remove the cone
upwards. This will allow the concrete to slump. The
rod is then placed horizontally on top of the cone and
a tape is used to measure the distance from the rod to
the top of the concrete. This distance is considered
the slump of the concrete
The lower the slump the greater the strength but the
harder the concrete is to work. The higher the slump
the lesser strength but the easier the concrete is to
work. When a structural engineer is involved, he
might specify that the concrete is to be 3000 psi with a
three to five inch slump. If this is specified, it is very
important to stay within these limits do not allow
anyone to add water to the mix on site without
permission from the individual doing the testing. If
the concrete is being pumped, there are additives that
can be added to the mix in order to allow a higher
slump but not jeopardize the strength of the concrete.
These additives can also be used in dry and windy
climates to allow a wetter mix and hopefully prevent
surface cracking due to the fast dehydration of the
concrete. If the concrete is tested, the slump might be
checked every fifty yards and the cylinders might be
taken at the same interval. Concrete cylinders are
taken and tested to verify the compressive strength
of the cured concrete. The cylinders are compressed
and broke at specified intervals. A cylinder broke
after 28 days should break at the designed strength or
greater.
Category Construction Glossary
