Why it's hard to follow up concrete cube testing
The Código Estructural (Spain's structural code, Real Decreto 470/2021, de 29 de junio; BOE-A-2021-13681) sets out how concrete compressive strength is checked on receipt: the sample is taken according to UNE-EN 12350-1, with its record, and the test specimens are crushed in compression at 28 days according to UNE-EN 12390-3, at least two for each determination.
In other words, the result arrives almost a month after the truck left the plant. By then the delivery note has already been invoiced and nobody remembers which raw materials went into that load. If crushing results are noted in a separate spreadsheet, matching each result to its delivery note is manual work every time.
And that's exactly what you need when a crushing result comes back low: to know what was produced, with which mix design and with which raw materials.