Non-Destrcutive Testing

Non-Destrcutive Testing

With advent in technology, Non-Destructive Testing (NDT) has created a niche in structural health monitoring without damaging the serviceability of the structure. NDT are very useful in inspecting, testing, evaluating materials and components for determining the condition of the in-situ structure. Thereby, forming the basis for devising repair methodology.

We have an experienced team dedicated for carrying out NDT. We have following equipments:

We have an experienced team dedicated for carrying out NDT. We have following equipments:

These tests are carried out to ascertain:

  • The homogeneity, porosity & density of the concrete
  • The values of dynamic elastic modulus of the concrete

UPV tests are carried out in accordance with Indian Standards: IS-13311 (Part I)

The tests are performed to measure the velocity of the ultrasonic pulse in the in-situ concrete using the instrument used to ascertain the concrete quality.

Interpretation of the result :

Pulse velocity Concrete Quality
>4.0 km/s Very good to excellent
3.5 – 4.0 km/s Good to very good, slight porosity may exist
3.0 – 3.5 km/s Satisfactory but loss of integrity is suspected
<3.0 km/s Poor and loss of integrity exist

These tests are carried out to ascertain:

  • To assess the likely surface/compressive strength of concrete
  • To assess the uniformity in the concrete
  • To assess the quality of the concrete in relation to standard requirements

Rebound Hammer tests are carriedout in accordance with Indian Standards: IS-13311 (Part II)

The tests are performed by pressing the hammer against the concrete and released to get a reading. The reading is read against the curve to get the compressive strength of concrete.

Interpretation of the result:

Average Rebound Quality of surface hardness/ Strength
>40 Very good
30 – 40 Good
20 – 30 Fair
<20 Poor and / or delaminated
0 Very poor and/or delaminated

These tests are carried out to ascertain:

  • Used for assessment or monitoring of the durability of reinforced concrete members where reinforcement corrosion is suspected
  • To determine if active corrosion may be occuring

Half-Cell Potential tests are carried out in accordance with ASTM C876 (1991) Standrad.

These tests include a voltameter used to measure the difference in potential between the reinforcing steel and a copper sulphate electrode in contact with the concrete surface. The value of potential difference provides with an indication of the presence or absence of active corrosion in the rebar.

Interpretation of the result:

Measured Potential (mV CSE) Probability of active corrosion
> -200 Less than 10%
-200 to -350 Uncertain
< -350 More than 90%

These tests are carried out to ascertain:

  • To determine the pH level, Chloride (Cl) and Sulphate (SO3) content in concrete

The higher values of either pH or Chloride (Cl) or Sulphate (SO3) content than the permitted level as per the Indian Standard Code indicate the presence of environment where the probability of corrosion of rebar is higher than normal.

The results are compared with the permissible limits of Indian Standard: IS-456 (2000)

Premissible Limits as per IS 456 (2000):

pH Not less than 8
> Cl (kg/m3) For PCC; maximum 2.0 kg/m3 of Cl
For RCC; maximum 0.5 kg/m3 of Cl
SO3 (mg/l) Maximum 0.4 mg/l

These tests are carried out to ascertain:

  • To determine compressive strength of in-situ concrete
  • To ascertain density of the concrete

Core tests are carried out in accordance with Indian Standards: IS:1199 and IS:516

Core sample is extracted from the structural member using a core cutting machine. The sample is then tested in the laboratory post core surface preparation is complete. Before testing the sample in Compressive Testing Machine, the prepared core sample is cured. The result thus obtained is corrected using applicable correction factor and converted to equivalent cube strength as per the Indian Standards.

+91 8451072218

+91 9867790953

C1/107, Rajgad CHS Ltd., Sarova Complex, Samta Nagar, Kandivali (E)
Mumbai 400101.

sccepl@hotmail.com

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