Concrete Sampling
Concrete Sampling
(OP)
I would like to know how to do sampling for a continuous work. I am in a railway project where thousands of foundation are to be done. Each day around 10 foundations (20 meter cube of concrete) are being done. Should I do sampling for each day separately or should i consider for whole project??? The concrete is obtained from same RMC plant.





RE: Concrete Sampling
A common specification for sampling is one set of specimens for each 100-150 cubic meters of concrete but not less than one set per day of placement.
What does your specification require?
RE: Concrete Sampling
Now, my question here is, should i take only one sample for 5 days of concreting (that would be 100 cubic meters considering 20 cubic meters of concrete each day) or should i take 1 sample for each day. The latter one would not be economic.
RE: Concrete Sampling
Dik
RE: Concrete Sampling
RE: Concrete Sampling
RE: Concrete Sampling
Thank you for response. I want to follow the 1 sample per day criteria. Please can anyone refer a code for the above said criteria. Which code to follow and which code has it defined clearly??
RE: Concrete Sampling
I said a minimum of 5 sets... apologies cvg, your response was to another message, and I missed that.
Dik
RE: Concrete Sampling
RE: Concrete Sampling
In Canada, CSA Standard A23.1-14 stipulates under Clause 4.4, 'Quality Control' the frequency of testing. It's pretty much as noted above and closely reflects the requirements of the ACI Code. My copy is at the office and when I return Friday, I'll scan the relative Clause and post it to you.
RE: Concrete Sampling
CONCRETE QC
WATER SHALL NOT BE ADDED TO THE CONCRETE MIX ON SITE UNLESS APPD IN WRITING BY THE CONCRETE SUPPLIER AND AUTHORISED BY THE ENGINEER
PROVIDE HISTORY OF CONCRETE MIX USE IN ACCORDANCE WITH CSA A23.1
TESTING SHALL BE IN ACCORDANCE WITH THE REQUIREMENTS OF CSA A23.1 UNLESS NOTED OTHERWISE
A MINIMUM OF THREE CYLINDERS SHALL BE TAKEN FOR EACH STRENGTH TEST, ONE CYLINDER FOR 7 DAY STRENGTH AND TWO CYLINDERS FOR 28 DAY STRENGTH
TEST CYLINDERS SHALL BE 6" DIA X 12" HIGH U/N
SLUMP TESTS SHALL BE TAKEN WITH EACH SET OF CYLINDERS TAKEN FOR STRENGTH TESTING
AIR CONTENT TESTS SHALL BE TAKEN FROM EACH LOAD UNLESS A REDUCED FREQUENCY IS AUTHORISED IN WRITING BY THE [OWNER | CONSULTANT | ENGINEER]
CYLINDERS FOR STRENGTH TESTS AND A SLUMP TEST SHALL BE TAKEN FROM AT LEAST EACH THIRD TRUCK
A MINIMUM OF THREE CYLINDERS FOR STRENGTH TESTS, AND A SLUMP TEST SHALL BE TAKEN EACH DAY FOR EACH DIFFERENT TYPE OF CONCRETE MIX DESIGN
WHERE THE FREQUENCY OF TESTING ABOVE WILL PRODUCE LESS THAN THREE TESTS FOR A GIVEN CLASS OF CONC, TESTS SHALL BE MADE FROM AT LEAST THREE RANDOMLY SELECTED BATCHES
IF LARGE VOLUMES OF CONCRETE ARE BEING SUPPLIED (OTHER THAN BY TRUCK), THERE SHOULD BE A MINIMUM OF THREE CYLINDERS TAKEN FOR STRENGTH TESTING, ONE AIR TEST AND ONE SLUMP TEST FOR EACH 100 CUBIC METRES OR PART THEREOF
CARE SHALL BE EXERCISED IN PROTECTING THE TEST CYLINDERS FROM DAMAGE
TEST CYLINGERS SHALL BE PROPERY CURED
IF TEST RESULTS SHOW A LARGE 'SCATTER' OF DATA, ADDITIONAL TESTING SHOULD BE PRESCRIBED
THE TESTING AGENCY SHALL FORWARD A COPY OF ALL TEST RESULTS DIRECTLY TO THE [OWNER | CONSULTANT | ENGINEER] AT THE TIME THE TEST RESULTS ARE FORWARDED TO THE CONTRACTOR
IF CONCRETE SPECIFIED IS IN EXCESS OF 35 MPA, THE CLIENT SHALL ARRANGE FOR THE GEOTECHNICAL CONSULTANT TO REVIEW THE CONCRETE BATCH PLANT
FOR TESTING MASONRY GROUT, REFER TO NOTES ON MASONRY CONSTRUCTION
Dik
RE: Concrete Sampling
DIK - I wasn't commenting on your reply, the OP said 1 sample, which is entirely inadequate for 5 days of work on up to 10 structures per day. Even 1 sample per day is probably inadequate. I would suggest:
minimum of the following:
at least 1 set per mix design, and
at least 1 set per structure, and
at least 1 set per day
So if you are doing 10 foundations per day, theoretically you may be taking 10 sets of cylinders, 1 for each structure
RE: Concrete Sampling
Dik
RE: Concrete Sampling
RE: Concrete Sampling
Sadly, I've seen specs that were written to say that each "placement" must have a set of samples taken. So if, for instance, one is placing concrete v-drains and he does one of 2 cubic metres and skips 20 m of length of the same drain as he had done that section a week earlier and does another of 2 cubic metres all from the same transit mixer, then they would have to do two sets. Ridiculous.
RE: Concrete Sampling
The information is based on the codes in effect at the time it was written.