Which is correct:

"A cat laid dead on the tarmack."


"A cat laid dead on the asphalt."


The word is "lay", past tense of "lie". "Laid" is the past participle of "lay". In my US dialect, "tarmack" is only a colorful way of saying airport paving. "Asphalt" is good, but don't think it means anything like "road". It's just a paving material.

A cat lay dead on the asphalt.

I agree. 'The tarmac' is an airport runway or apron made out of asphalt. Common noun. Asphalt is a flexible, blackish, road material made out of tar or bitumen. I'm from Canada, this is how we use it in North American English.

Tarmac (short for tarmacadam) is a road surface material patented in 1901 in the UK. Proper Noun. Apparently they use the word differently in UK.

Using it in a sentence would have to include specific qualifications to tell the reader location and situation.