Concrete strength of compression.
Concrete strength of compression.
(OP)
New to forum, not sure where to post this question- product is an 8x8x12 inch solid block, manufactured with the 12 inch dimension horizontal. Will it have the same compression strength horizontally as vertical? Thanks, 4evrjarhead.





RE: Concrete strength of compression.
Dik
RE: Concrete strength of compression.
Depending on the testing machine, there could be some effects if a platen plate is used and it can deflect and concentrate the load in the center of the sample.
I ran into this with some 2 block high 12" CMU prism samples showed a false compressive strength for the lab existing equipment.
The testing machine was only a 200,000 T-O and the lab used a thinner platen because of the usual vertical opening. They installed a thicker, more rigid platen and test results were about 20% higher.
If I have not requested photos for the failure mode, it could have been passed over as a failure to meet the specifications. The designing/spec writing firm was a little embarrassed even though the testing procedure the testing of a 12x16x16 solid sample.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Concrete strength of compression.
Dik
RE: Concrete strength of compression.
RE: Concrete strength of compression.
No change in the wall strength due to testing orientation. As far as the manufacturing, 99% of the time the 12" would be a horizontal dimension because of the manufacturing methods and equipment used. The failure mode is not dictated by the manufacturing orientation.
There is a different failure mode between lab testing and actual installed units. The masonry units in a wall are generally controlled by the dimensions of a panel with everything gravitating toward the proverbial 45 degree line, except for flexure. - Once mortar is involved the individuality of the masonry units are converted to a panel. - The strength properties of he mortar has very little effect on vertical loads or flexure.
Just to confuse things, hollow CMUs are always laid the the bottom side(as manufactured) face up. - Easier to handle and spread mortar on.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Concrete strength of compression.
Dik
RE: Concrete strength of compression.