PE Exam Practice Problem #58: Materials | Concrete - Compressive Strength

Welcome to SolvedIn6: Free practice problems for the Professional Engineering Exam! Each question is styled after those created by the NCEES, and is usually solved in under 6 minutes, which is the average time you will have to solve each question on the Professional Engineering Exam.
In this problem, we are given some background information about 3 concrete cylinders, and asked to find their 28-day compressive strength.
If you’re completely stuck, it might be hard to use the reference manual here - but its not impossible. Searching for the word “compressive” or “fc” will EVENTUALLY get you to the section on Material Properties and Testing. From here, it notes that a strength test shall be the average strengths of AT LEAST 2 cylinders. Since we have 3 cylinders, we will use all 3.
Now, since the results are asked for in PSI, its pretty easy to see what we need to do. The axial compressive failure loads are given in the problem statement in pounds, and the dimensions of the cylinders are given in inches. Solve for the top or bottom surface areas of each cylinder, and divide the failure values by these numbers. Then, take the average of those values.
If you would like more Materials practice problems, please check out the rest of the playlist which this video is part of.
Please note that newer versions of the reference manual may have been released since this video was recorded. The search terms are usually still correct, but the page numbers listed in the video will be different.