Masonry f'm Inspection
Masonry f'm Inspection
(OP)
Some Building Codes require f'm checked periodically. Does that mean having mortar checked by testing lab doing cube samples, or is it just observing mortar being mixed, from bags labeled correctly as to Type (M, N, S, etc) and CMU being placed?
I am specifically referring to NYC BC Chapter 17, Table 1704.3 (Level 2), and for that matter whatever the IBC 2015 also says for New York State work.
Of course its always a good idea to use labs to check mortar samples, but my question is specific to BC requirements.
I am specifically referring to NYC BC Chapter 17, Table 1704.3 (Level 2), and for that matter whatever the IBC 2015 also says for New York State work.
Of course its always a good idea to use labs to check mortar samples, but my question is specific to BC requirements.






RE: Masonry f'm Inspection
The over-riding factor in determining the f'm is the compressive strength of the block, that can be verified by pulling samples. The strength of the actual mortar is not a major factor and can be verified by observing the mixing procedures and proportions.
Strength testing of mortar is only used for research and not for construction verification. The ASTM standard for mortar, in the the appendix note states that the weakest mortar should be used to take advantage of the other properties of mortar, such a workability.
You can get a 5000 psi f'm with 2200 psi mortar if you can even find a need for such strengths. It may require a higher strength block that can be verified or specified in advance of construction.
Testing of job site prisms is unreliable, costly and time consuming.
Read the ACI 530 document regarding the design and construction of masonry. - The ACI 530 is the "bible" for masonry design and construction domestically and internationally and is normal referred in most civilized codes.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
RE: Masonry f'm Inspection
Most of the time we avoid masonry prism testing and simply used proportional specifications for masonry.
Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies
RE: Masonry f'm Inspection
Diik