Specification Concrete Work Structure


Definition of the rules of the composition in the manufacture, in quality control, routing
and in facilitating the work of normal concrete.


Inert for mortar and concrete.

ASTM C125-82nd-Terms relating to concrete and concrete aggregates.
Specifications are subject to the terms of reference for the following:

Inert for concrete of hydraulic binders and Hydraulic Mortars;

Cement, lime and pozzolanic Air;

Construction. Reinforcement for reinforced concrete and pre-stressed;

Construction. Madeira.

The composition of each of the concrete should be used to meet the specified
ENV NP 206 in force and shall be established by the Contractor according to the characteristics
sought and it proposes to employ components.

Contractor will charge the studies of composition of concrete, which can be
given in particular the quality 1.

The tests needed to establish the composition of the concrete tests are

When necessary, the contractor for preparation of specific reports of
studies of composition of concrete, which should be submitted to the Owner of Work before
be initiated the manufacture.

The Contractor may at any time, replace the composition of a concrete, except
is expressly prohibited by applicable normative documents. In this case, however,
will be repeated the steps necessary to establish the new composition.


The tests and techniques used in the manufacture of several of the concrete work will be established
by the contractor, however with the requirements of the Project and RBLH and the
Construction (materials, elements and conduct of the work) Rev. 05 / 1

Specifications and standards apply.

In the manufacture of concrete components will be used with the features adopted in the
establish the composition and the following tolerances:

a) modulus of fineness of inert not deviating more than 0.20 of the module of fineness
inert as the basis for the establishment of the composition, and its
determination made as defined in ASTM C125-69 (Terms relating
to concrete and concrete aggregates);

b) the cement to be used in accordance with specific composition of the concrete should not
significantly lower quality characteristics of the batch was the basis for the
establishment of the composition. It is understood that this happens when the result
the test for determining the strength of mortar at 28 days is normal
less than 50 kg/cm2 as the values assigned to that lot.

Tests of control that become necessary, according to the techniques adopted,
tests are considered mandatory.

When there is need for the manufacture of concrete under temperature conditions
unfavorable, the Contractor will propose the adoption of the Work Owner of special measures
wishes to adopt.

Verification and inspection

Regardless of the action performed by others, the Owner shall perform the Work
monitoring and verification activities required by RBLH.

The contractor preparing the reports of the manufacture of concrete under RBLH.

The book of record of the work will be integrated into the daily log of work, as is

Specification Concrete Work Structure


The reception of the concrete shall be in accordance with the established and in
specifications and standards apply.

If other rules are not displayed, the division into lots is established by prior agreement
between the Contractor and Owner of Work, each batch can refer to parts of the building, the whole
construction, lots of parts, the volume of concrete made or at intervals of time of manufacture.
Construction (materials, elements and conduct of the work) Rev. 05 / 1

In any case, the same lot where concrete cover with the same characteristics of
manufactured by the same sheet of manufacture.

The sampling will be performed during the manufacture of concrete
corresponding to their lot.

In sampling for the determination of parameters of statistical distribution of tensions
of rupture should be taken at least one sample per 10 to 50 m3 of concrete, and never
less than one daily sample. If the number of samples is less than 20, the concrete will not be accepted
if any of the results of the determination of tensile strength at 28 days is less than the value
specified characteristic.

As mentioned in previous point sampling, sampling will be conducted in accordance
with the requirements in concrete. Preparation of samples for testing the compression and

In sampling for determining the maximum size of the inert, the dosage
binder, the water-binder ratio, the content of air incorporated and the consistency should pick up by
least one sample per 40 to 200 m3 of concrete, and not less than one sample per
period of four days of operation.

The test for reception of concrete type B, according to the specified
RBLH is the determination of tensile strength at 28 days, this test is mandatory for
specific qualities of 1 and 2 should be done simultaneously.

The test set for the receipt of specific types of BD, in classes 1 and 2, according
with that specified in RBLH are:

a) determination of tensile strength at 28 days;

b) determination of:

dosing of ligands;

relation water / binder.

These tests should be made in accordance with determination of the composition of
fresh concrete.

The tests laid down for receiving the specific type of Class 3 BD, according to
specified in RBLH are:

a) determination of tensile strength at 28 days;

b) determine the level of air incorporated in samples of fresh concrete.

This test should be done according to the Determination of the content in the air
fresh concrete.

The tests on the tensile strength after 28 days are required.

In the concrete study of the composition includes specifications for consistency, this
will be determined by the procedure established in the following documents:

The maximum size of the inert use is calculated based on the definition established
in the standard.

Given the particular characteristics of concrete, a decision of approval or rejection
these materials may in general be known after its application to work in the case of
material be rejected, will be demolished the corresponding part of the work, unless another solution is
agreed between the Contractor and Owner of Work, guaranteed that the regulations
in force.

On receipt of specific and based on the results of the tests, the deviation will be calculated
standard or the coefficient of variation of the statistical distribution of the tension of rupture at 28 days and
characteristic of this tension. This calculation is performed according to terms contained in
attached to RBLH. The material of a lot shall be rejected if any of the values is less than the
value specified in the document above.

Besides the rule established ago will still reject the concrete if the average of results
trial for any of the others do not meet the values specified in the study of
composition, with the tolerances specified in RBLH.
Construction (materials, elements and conduct of the work) Rev. 05 / 1

Placement, compaction and conservation of the concrete

The transport, deposit and placement of concrete should be conducted in accordance with the
the prescribed standard.

To avoid segregation, the concrete should be placed as close as possible to their
final position and in horizontal layers of thickness not exceeding 50 cm. With the same
objective, it should not drop the concrete vertically over 1 m high, or through
a mesh of armor, except when done through the placement of hoses.

The placing of the concrete work to be done so that, once
within the shuttering, yet remain plastic and looks like the concrete is fresh.

The use of the manuals for the transport of fresh concrete shall be accepted only when
the case of small volumes and distances. During transport should be to have the maximum
care to avoid bumps and vibrations that would lead to segregation.

In the case of the use of tubes inclined in the transport of concrete, they must meet
the following conditions:

be metal or wood covered in metal;

have an inclination vertical / horizontal within 1 / 2 to 1 / 3, so that the concrete
moves fast enough to keep the tube clean and sufficiently slowly
to avoid segregation of materials.

At the end of the tube of transport should be a chicane to help avoid segregation
or the concrete must be discharged directly into the final place in a bucket or through
a hose.

In betonagem of walls and pillars should be using hoses or buckets, to avoid
the free fall of concrete through the reinforcement cage.

In the case of transport by pumping, the equipment must be appropriate, without seams
Y and with a capacity of pumping adequate.

In the case of transport by pumping, it should be held before the test of consistency and
after the transport.

The increase in consistency, in the case of transport by pumping, should not
correspond to a decrease in test "slump" of more than 3 cm.

May be used or temporary openings in sidescuttles cofragens of walls or pillars,
to, during betonagem to limit the free fall of concrete to less than 1 m.

Horizontally, the openings mentioned above should not be a
more than 1.50 m or 2.00 m, thereby limiting the horizontal displacement of the concrete and avoid

The betonagem of each element, ie the volume of any Béton, limited by
shuttering surfaces of joints and the construction or expansion, should be so
continued without interruption, for it will be a monolithic unit.

The Draft Implementation indicate the exact location of the expansion joints and
construction. When it does not, the Contractor shall submit the plan betonagem,
including the location, the approval of the Owner of Work.

Should place a time with a minimum duration of 48 hours between
betonagem of two successive elements.

The betonagem of beams or slabs should not be initiated before the concrete walls or in
pillars in contact with them, have reached their full original settlement.

Immediately after placing, the concrete must be consolidated, so approved,
to fully involve the reinforcement and to prevent the formation of voids. On consolidation
the concrete may follow up the recommendations of ACI Committee 609 document (Consolidation
of Concrete).

Each horizontal layer placed should be consolidated through the use of
vibratory equipment approved. By vibrating a layer, the vibrator should penetrate the layer
behind, so that the two are soldered together and interpenetrate.

Will not be allowed the use of vibrators to push the concrete horizontally within
the mold. It is recommended the use of high-frequency vibrators with a minimum of
7 000 rpm, for the consolidation of the concrete inside the mold. The concrete should not be vibrating
too long, because this may cause the segregation of fine elements.

In cold weather, should take the following measures:

the mixing of water and / or aggregates should be heated so that the
temperature of fresh concrete obtained not less than 13 ° C;

the concrete should be kept to a minimum temperature of at least 10 ° C for a
period of not less than 5 days after betonagem;

should follow up the recommendations in ACI 306-66 for betonagem in cold weather.

In warmer weather, unless the temperature is a maximum of 32 ° C and with a tendency
to download, it should take special measures during the mixing, placing and prey,
including the following:

the inert and cement should keep in a cool place;

may be using a retardant additive of prey;

you will cool the water by mixing of cooling or replace that part by
scrapings of ice or ice crumble;

the temperature of the concrete at the placement, should never exceed 32 ° C;

the cofragens and rods of armor should be cooled to temperatures below 30 ° C,
It is sprinkled with cold water;

should follow up the recommendations in ACI 605-59 for betonagens in warm weather.

The finishing of the free surface should meet the specifications required
by the work on which they are made.

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