Answer :
Final answer:
The compressive strength of concrete designated for compression is greater than 3000 psi at 42 days.
Explanation:
The student's question is asking about the concrete which is designated by compressive strength that has a strength greater than a certain psi at 42 days. The ultimate compressive strength of concrete is given as 20 × 106 N/m². To convert this to psi (pounds per square inch), we have to multiply by a conversion factor which is approximately 145.038. This will give us a compressive strength of approximately 2900 psi. Hence, the correct option is b) 3000 psi. The concrete with designated compressive strength indeed has more than this value at 42 days.
Learn more about Compressive Strength here:
https://brainly.com/question/31463020
#SPJ11
