The core test of concrete is a procedure for evaluating the compressive strength and quality of hardened concrete by drilling cylindrical cores from the structure. This testing helps assess structural safety, quality, and thickness verification, along with investigating any distress in the concrete. Guidelines for core testing, including procedures and criteria for acceptable strength, are also outlined according to Indian standards IS 516:1959 and IS 456:2000.

1. CORE TEST OF CONCRETE
PREPARED BY
AMRIT PANDEY
(PUL078BCE023)

2. CORE TEST
The core test of concrete is a procedure used to assess the
compressive strength and quality of hardened concrete in situ (in place). It
involves drilling and extracting cylindrical cores from the concrete structure
using a diamond-tipped core drill. These cores, typically 4 inches in diameter and
varying in length based on the structure's thickness, are then subjected to
compressive strength testing in a laboratory.

3. WHY CORE TEST ?????

4. WHY CORE TEST ?????
1.Compressive Strength Evaluation:
Determine the in-place compressive
strength of concrete, which is crucial for assessing structural capacity and safety.

5. WHY CORE TEST ?????
2.Quality Assessment:
Evaluate concrete quality by examining factors such
as uniformity, homogeneity, and the presence of defects like voids, cracks, or
improper consolidation.

6. WHY CORE TEST ?????
3.Thickness Verification:
Confirm the actual thickness of concrete members,
especially when as-built dimensions are needed for structural analysis or
retrofitting.

7. WHY CORE TEST ?????
4.Investigation of Distress:
Investigate the causes of distress, such as cracks or
spalling, by examining core samples to determine underlying issues like poor
concrete quality, inadequate reinforcement, or environmental exposure.

8. PROCEDURE OF CORE TESTING

9. PROCEDURE OF CORE TESTING
1.Core Drilling:
Use a diamond-tipped core drill to extract
cylindrical cores from the concrete structure. Cores are
typically drilled perpendicular to the surface and are
carefully handled to avoid damage.

10. DBE 201 Diamond Core Drill Rig
Source : https://www.csunitec.com/

11. PROCEDURE OF CORE TESTING
2.Core Extraction:
Carefully remove the core samples without
causing significant disturbance to the surrounding concrete.

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14. PROCEDURE OF CORE TESTING
3.Testing:
Transport the cores to a laboratory for
compressive strength testing using standardized procedures.
Cores may also undergo petrographic analysis, chloride ion
content testing, or other tests depending on project
requirements.

15. TESTING
According to the Indian Standard (IS)
516:1959, concrete core tests for compressive strength
should follow some guidelines .

16. GUIDELINES

17. GUIDELINES
1. Core diameter
The core's diameter should be at least three times the
maximum size of the concrete's coarse aggregate, and at
least twice the maximum size of the coarse aggregate in the
core sample. The preferred diameter is at least 75 mm, but
not less than 50 mm.

18. 2.Length to diameter ratio
For compressive strength testing, the length to diameter
ratio should be between 0.90:1 and 1.10:1 when comparing
against a 1:1 specimen (cube).

19. GUIDELINES
3.Core capping
Use epoxy material to cap the core. The caps should be as
thin as possible, but no thicker than 5 mm on average.
Before capping, make sure the core's surface is clean, dry,
and free of loose particles , smooth ,flat surfaces
perpendicular to the longitudinal axis.

20. GUIDELINES
4.Core preparation
Place the core specimen with the collar and plate in moist
air with a temperature of 27± 2°C and a relative humidity of
at least 90%. Remove the plate and collar when the mortar is
hard enough to handle without damage.

21. GUIDELINES
4.Number of cores
Test at least three cores.

23. GUIDELINES
5.Concrete strength
Concrete needs 28 days to reach a hardened state. According
to IS 456:2000, the concrete in the member represented by a
core test is acceptable if the average equivalent cube
strength of the core is at least 85% of the cube strength of
the specified concrete grade, but no individual core can be
weaker than 75%.

24. PROCEDURE OF CORE TESTING
4.Calculation of Compressive Strength:
The compressive strength 𝑓𝑐 is calculated using
the formula:
𝑓𝑐=𝑃/𝐴
where 𝑃 is the maximum load applied to the specimen and 𝐴
is the cross-sectional area of the core.

25. PROCEDURE OF CORE TESTING
5.REPORTING :
After calculating the compressive strength test
from the core sample it is then compared with the result
came from the sample specimen of cube and cylinder of
same grade. And it will be acceptable according to the IS
456:2000 ,if it strength is at least 85% the equivalent
strength of cube .
Individual core strength cannot be less than 75% of the equ.
Cube strength.

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31. REFERENCES
1. https://chatgpt.com/
2. https://law.resource.org/pub/in/bis/S03/is.516.1959.pdf
3. https://backend.delhimetrorail.com/documents/1284/Coretest050421.pdf

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33. ANY QUERIES????????