The most common and most likely answer to this crossword clue is the 10 letter word INCARNATED
I've seen this crossword clue in The Times
I
N
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A
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Buddy explains!

The straight part
We know that "Made concrete" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case made concrete = incarnated.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INCARNATED mean?
INCARNATED verb- To embody in flesh, invest with a bodily, especially a human, form.
- To incarn; to become covered with flesh, to heal over.
- To make carnal; to reduce the spiritual nature of.
- To put into or represent in a concrete form, as an idea.