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INSPECTION AND GOOD CONSTRUCTION PRACTICES Presentation Transcript
1.INSPECTION,GOOD CONSTRUCTION
PRACTICES AND CODAL PROVISIONS
PRACTICES AND CODAL PROVISIONS
2.INSPECTION AND GOOD CONSTRUCTION PRACTICES
3.GOOD CONCRETE
Concrete in the fresh state should be cohesive,so that it can be transported and placed without segregation.
Many properties of concrete are related to
its compressive strength:
1 Density
2 Impermeability
3 Impact-resistance
4 Abrasion-resistance
Concrete in the fresh state should be cohesive,so that it can be transported and placed without segregation.
Many properties of concrete are related to
its compressive strength:
1 Density
2 Impermeability
3 Impact-resistance
4 Abrasion-resistance
4.The W/C ratio also controls the permeability
of concrete.
The construction should result in satisfactory strength,serviceability and long-term durability.
of concrete.
The construction should result in satisfactory strength,serviceability and long-term durability.
5.QUALITY ASSURANCE
Qualily assurance in construction relates to:
1 Proper design.
2 Use of satisfactory materials and components.
3Proper workmanship in the execution of works and finally,
4 Proper care during the use of the structure
including timely maintenance and repair..
Qualily assurance in construction relates to:
1 Proper design.
2 Use of satisfactory materials and components.
3Proper workmanship in the execution of works and finally,
4 Proper care during the use of the structure
including timely maintenance and repair..
6.The job of Q.C and Q.A would involve quality audit of both the inputs & outputs.
INPUTS in the form of materials for concrete,WORKMANSHIP in all stages of batching,mixing,transportation,placing,
compaction and curing & the related plant,
machinery and equipment resulting in the form of concrete in place.
INPUTS in the form of materials for concrete,WORKMANSHIP in all stages of batching,mixing,transportation,placing,
compaction and curing & the related plant,
machinery and equipment resulting in the form of concrete in place.
7.The Quality assurance Plan shall include:
a)Test reports and manufacturer,s certificate
for materials,concrete mix design details;
b) Pour cards for site organization & clearance for concrete placement;
c)Record of site inspection of workmanship,field tests;
d) Non-conformance reports, change orders;
e)Quality control charts& statistical analysis.
a)Test reports and manufacturer,s certificate
for materials,concrete mix design details;
b) Pour cards for site organization & clearance for concrete placement;
c)Record of site inspection of workmanship,field tests;
d) Non-conformance reports, change orders;
e)Quality control charts& statistical analysis.
8.QUALITY CONTROL CHARTS ARE
RECOMMENDED WHEREVER THE
CONCRETE IS IN CONTINUOUS
PRODUCTION OVER CONSIDERABLE
PERIOD.
RECOMMENDED WHEREVER THE
CONCRETE IS IN CONTINUOUS
PRODUCTION OVER CONSIDERABLE
PERIOD.
9.STANDARD DEVIATION
Standard Deviation is a good measure of
Q.C.
GOOD control means lower S.D (say 3 or
4 N/mm2).
At least 30 test results should be used to
calculate Standard Deviation.
Each test result is average of 3 cube test
results at 28 days.
Standard Deviation is a good measure of
Q.C.
GOOD control means lower S.D (say 3 or
4 N/mm2).
At least 30 test results should be used to
calculate Standard Deviation.
Each test result is average of 3 cube test
results at 28 days.
10.CALCULATION OF S.D
11.WORKMANSHIP & CODAL PROVISIONS
Concrete supplied by RMC plants shall be preferred.
The grading of coarse aggregate should be controlled by obtaining the coarse aggregate in different size fractions & blending them in right proportions to satisfy the grading limits prescribed in IS 383.
The grading of coarse & fine aggregates should be
Checked as frequently as possible.
Concrete supplied by RMC plants shall be preferred.
The grading of coarse aggregate should be controlled by obtaining the coarse aggregate in different size fractions & blending them in right proportions to satisfy the grading limits prescribed in IS 383.
The grading of coarse & fine aggregates should be
Checked as frequently as possible.
12.REQUIREMENT FOR COMBINED GRADING
13. It is important to maintain the W/C at its correct value.
For this,moisture content of coarse &fine aggregates should be determined as frequently as possible.
For this,moisture content of coarse &fine aggregates should be determined as frequently as possible.
14.MIXING OF CONCRETE
The mixing time should be at least
2 minutes in a drum mixer.
For more efficient mixers(in a batching & mixing plant or in an RMC plant),the mixing time may be about ½ minute.
(Manufacturer”s recommendation may be
followed)
The mixing time should be at least
2 minutes in a drum mixer.
For more efficient mixers(in a batching & mixing plant or in an RMC plant),the mixing time may be about ½ minute.
(Manufacturer”s recommendation may be
followed)
15.PLACING OF CONCRETE
The concrete shall be placed & compacted
in its final position as early as possible & before initial setting of concrete.
Care should be taken to avoid displacement of reinforcement or movement of formwork
Max. free fall of concrete may be 1.5m.
The concrete shall be placed & compacted
in its final position as early as possible & before initial setting of concrete.
Care should be taken to avoid displacement of reinforcement or movement of formwork
Max. free fall of concrete may be 1.5m.
16.CONCRETE ADMIXTURES
The dosages of retarders,plasticizers & superplasticizers shall be restricted to 0.5,1.0 and 2.0% respectively,by weight
of cementitious materials,unless a higher
value is agreed upon between the
manufacturer & the constructer based
on performance test.
The dosages of retarders,plasticizers & superplasticizers shall be restricted to 0.5,1.0 and 2.0% respectively,by weight
of cementitious materials,unless a higher
value is agreed upon between the
manufacturer & the constructer based
on performance test.
17. Concrte should be thoroughly compacted.
Each 1% void can reduce the compressive
strength of concrete by 5%.
Over- vibration & under- vibration are harmful and should be avoided.
Fresh concrete should be thoroughly compacted near the construction joints.
Each 1% void can reduce the compressive
strength of concrete by 5%.
Over- vibration & under- vibration are harmful and should be avoided.
Fresh concrete should be thoroughly compacted near the construction joints.
18.CURING OF CONCRETE
Exposed surfaces of concrete shall be kept
continuously damp or wet condition by ponding or by covering with wet burlap,hessian etc.
For Concrete with blended cement or mineral
admixtures(flyash or ggbs or silica fume),
the curing period should be increased.
Exposed surfaces of concrete shall be kept
continuously damp or wet condition by ponding or by covering with wet burlap,hessian etc.
For Concrete with blended cement or mineral
admixtures(flyash or ggbs or silica fume),
the curing period should be increased.
19.CURING COMPOUNDS
Curing compounds may be used in case of scarcity of water or for high-
rise structures e.g bridge piers,RCC
columns,chimneys and concrete roads.
These compounds( wax-based or resin-
based) are spray-applied on exposed
concrete surfaces,as soon as possible
after the concrete has set and when
there is no water scene is visible on the surface.
Curing compounds may be used in case of scarcity of water or for high-
rise structures e.g bridge piers,RCC
columns,chimneys and concrete roads.
These compounds( wax-based or resin-
based) are spray-applied on exposed
concrete surfaces,as soon as possible
after the concrete has set and when
there is no water scene is visible on the surface.
20.SOME OF INDIGENOUS CURING COMPOUNDS
1 EMCORIL
2 CONCURE(W B)
3 ROFFCURE W B WHITE
4 FREECURE
5 CUREWELL –W B
6 CHEMISTIK
7 ANTISOL
Coverage: 4-5 m2/Kg
1 EMCORIL
2 CONCURE(W B)
3 ROFFCURE W B WHITE
4 FREECURE
5 CUREWELL –W B
6 CHEMISTIK
7 ANTISOL
Coverage: 4-5 m2/Kg
21.CONCRETE COVER
Concrete cover should be adequate in concrete structures.
Inadequate cover to reinforcements
will result in corrosion of reinforcements.
Concrete cover should be adequate in concrete structures.
Inadequate cover to reinforcements
will result in corrosion of reinforcements.
22.NOMINAL COVER TO REINFORCEMENTS
23.VACUUM-DEWATERED CONCRETE
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