I got a set of problems from a co-worker for the construction section of the PE exam, and have a couple of questions.
1. when solving concrete mix problems, once you've gone through all of the steps listed in the CERM and determine the volume of your batch, you can go in and determine the quantities of each element (fines, coarse, water, etc.) for a specific quantity of concrete (say 25 yards). In the CERM, if you found that you would need 3.3 bags of your concrete to do a job that required 25 yards of concrete (made up numbers here), you assume, as you would in the real world, that you need 4 bags of concrete (you can't buy .3 bags of concrete). I have done a couple of example problems from other sources where to get the correct answer, you use the decimal. What is the standard? I thinmk the CERM method makes more sense, and it drastically changes your answer if you do one way or the other.
2. mean compressive strength. given a set of data from a 28 day sample, and asked what the mean compressive strenght was, I figured that you took the mean of the break values (in pounds) and divide it by the area of a cylinder's end. doing this I not only got nothing close to the supplied answers, but when i even reverse engineered from the answers, did not get an answer that made sense. Am I way off here?
TIA
1. when solving concrete mix problems, once you've gone through all of the steps listed in the CERM and determine the volume of your batch, you can go in and determine the quantities of each element (fines, coarse, water, etc.) for a specific quantity of concrete (say 25 yards). In the CERM, if you found that you would need 3.3 bags of your concrete to do a job that required 25 yards of concrete (made up numbers here), you assume, as you would in the real world, that you need 4 bags of concrete (you can't buy .3 bags of concrete). I have done a couple of example problems from other sources where to get the correct answer, you use the decimal. What is the standard? I thinmk the CERM method makes more sense, and it drastically changes your answer if you do one way or the other.
2. mean compressive strength. given a set of data from a 28 day sample, and asked what the mean compressive strenght was, I figured that you took the mean of the break values (in pounds) and divide it by the area of a cylinder's end. doing this I not only got nothing close to the supplied answers, but when i even reverse engineered from the answers, did not get an answer that made sense. Am I way off here?
TIA