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Hello members I hope this thread finds you well. My query today is related to compressive strength of concrete bored piles. The issue is that pilegroup with 24 no of piles have been casted almost two years ago but there were observations regarding quality control on couple of piles in the group which are not known. Now the higher-ups are recommending to resume the project again and unfortunately I'm the incumbent and have to propose a methodology. Now the question is that since the piles are already buried underground, which procedure shall be adopted to predict its compressive strength near to its actual. Your suggestions will highly be appreciated. Thanks.

Assalam-o-Alaikum! Dear All, I have some questions, someone might help me get clear my concepts. Thanking you in advance! 1. Is there any other method to access fresh concrete compressive strength other than that we cast concrete cylinders/Cubes during casting and test them on 7 days or 14 days or 28 days and judge the strength. 2. Before poring the concrete, how can we ensure that the concrete has correct water cement ratio i.e. The amount of cement is as per required amount? 3. What is the problem with using cement (having some lumps) in preparing concrete. 4. Complete Process of Concrete Poring? 5. How to find yield strength of steel in field? Is there any method to judge it other than tensile test report or Not?

In concrete compression test, normally 150mmx150mmx150mm concrete cube samples is used for testing. Why isn’t 100mmx100mmx100mm concrete cube samples used in the test instead of 150mmx150mmx150mm concrete cube samples?

This one is mostly a practical issue.. If ever cube strength fails after 28 days, say for example the concrete compressive strength with which the structure was designed was 30MPa, and from cube test or non-destructive testing, the compressive strength has been found to be half, 15MPa only. Most consultants usually instruct demolition of the concrete element and re-casting. From a calculation which i made manually, I found that fcu(symbol as per BS 8110) has very little effect on reinforcement calculation. Even if fcu is halved when calculating again, new steel reinforcement calculated may increase by only 2-3%. Furthermore, fcu affects the value of Modulus of elasticity E, which in turn affects stiffness of the member producing a change in deflection of beams for example. But the effect is not so much prominent though, it may still pass in deflection also. Can anyone ellaborate more on this issue, if ever cube strength fails on site, final instruction will be based on what for an engineer supervising on site.

Hello..does anybody have any reference to this topic.. I know it is used in the connection between slabs and vertical elements when the ratio of compressive strength of each exceeds 1.5 Thanks in advance