Concrete Mix Design

Is concrete mix design something that is common to show up on the PM construction section?

I am thinking proportions, etc. Also does anyone have any good sample questions on concrete for the PM. I have the Portland Cement Concrete Mix Deisgn book. I just need to brush up on it..

Thanks,

Mike

I was working over NCEES Construction PM problem # 512. If the questions are similar to this type, I would be in good shape. I do have one questions however. It tells you the aggregate is SSD condition. Is this assumption always made? In Ruwan, he made no mention of SSD or anything else. How would it be affect the process if it wasn't SSD. Would you have to take a moisture content of the aggregate and somehow based on specific gravity solve for the SSD?

Thanks,

Mike

Most rock is not that porous so It shouldn't be an issue, but the SSD condition is specified so that the water added is available for concrete hydration. If the rock is porous and absorbs the water then the w/c ratio will be off.

Be prepare the work concrete forwards and backwards, including the use of specific gravities

Forwards & backwards. I am assuming you mean based on whats given and what they want you to find? When I started reviewing in the PCC Mix Design book, they basically give you a ratio and some Specific Gravities along with the weight of ONE of the incrediants. From there you are to find all the weights, convert to volume, then find the volume of water and from there you can find the water/cement ratio in gallons/sack or just gallons of water or weight of water, It was spot on when I found a virtually identical problem in the NCEES review manual. How else can they make it difficult?

Mike

Thats pretty much what I meant, the good thing is once you see what you have you can figure what you need to get the the endpoint (does that make sence??). Sounds like you are ready for some concrete probs. The NCEES review manual is a good reference and does match the difficulty of the test.