In order to check the strength of the concrete in place, in order for the batch to match the specified strength, it is important that the cubes are made to the correct standard. Cubes must be manufactured in accordance with British Standard (BS) 1881: 1983 Testing Concrete.
Necessary equipment:
Mold to create a test cube
wrenches
scoop
Steel float or spatula
Sealing beam
Formwork Oil
Curing tank
Sample collection bucket
As soon as the truck arrives at the site, a sample must be taken before adding water to the mixture. Take a sample in the specified area set for the manufacture of cubes. You should have already assembled the forms so that you can immediately start filling them while the concrete is still operational. It would also be nice to cover the inner surface of the molds with formwork oil so that it would be easy to disassemble later.
Usually, 3 forms should be made for each concrete sample so that the concrete can be tested after 7 and 28 days, and the 3rd mold can be held as a spare.
Using a bucket, fill each mold to about a third full and compact the concrete with a sealing rod with uniform strokes over the area of the mold. Usually, for full compaction, it is necessary to provide up to 35 strokes, as well as to ensure the absence of air voids, but be careful not to exceed them, as this can separate the unit from the cement.
Next Fill the molds to two thirds and repeat the required seal before filling to the top and seal again. After the filled cube forms sufficiently comment on the concrete surface with a spatula and clean the excess concrete from the form.
Ensure that individual cubes can be identified using appropriate labels, which should at least show the date, time and cube ID.
After the cubes are cured, they should be covered with a wet mat and stored for 16-24 hours in an area where the temperature is between 20 and 30 degrees Celsius.
Once the required time has passed, and the cubes have reached the required strength, which must be molded without damaging the sample, they should be deformed, marked with a marker or pencil and placed in a tank for curing at a temperature of 27-30 degrees Celsius until they are ready for testing
After completion of the molding, the mold should be cleaned, assembled and prepared for the next set of samples.
