Is there any utility of testing concrete,cement sample when sample not collected by testing authority.?

Question

As per code,sample should be collected as per sampling criteria.When sample collecting authority and testing authority are different,no body can be blamed for false test results.

Answer 1

For testing which was not taken for testing(Cubes) when the time of placing, there is no of methods to test the soncrete.

Destructive and non destructive methods.

Most of the construction firms enage core cutting method i.e 3 nos 75-100 mm dia cores will be extracted from the concrete and tested for compressive strength. If the test results are 85% of the intended grade of concrete, the resuts is ok provided that out of three samples no individual core strength not less than 75%.The testing should be witnessed by structural consultants and all other related to that project.

Some no destructive methods are rebound test and ultrasonic test but we can rely only on core test.

Answer 2

If the testing was not done per ACI or some other established method (caltrans, etc), then the results could not be considered reliable. If it is coming from a ready mix plant, they likely have a history of breaks and other clients have breaks of the same mix. If you need to know for sure, you will need random cores. The will break these and they need to be close enough to each other to be considered representative.

Answer 3

the quality can be established with samples collected by corecutter,using ultra violet raysetc.

Answer 4

That is why buildings under construction collapsed news comes out.