AAC Masonry Parapet

[bookowski]

I've got a client and architect that typically use AAC block for the first two courses of their masonry parapets (on cip concrete buildings). Their purpose is the better thermal performance of AAC.

I've never worked with AAC. I see that it's addressed in ACI 530 and the strength design is clear. I'm not clear on construction details. These appear to be solid blocks only, not cellular units, and they come in 24" lengths. I want to make sure I'm understanding how you build with this.

- Is it correct that vertical reinforcement runs between adjacent blocks
- They want 2 courses of AAC and then standard CMU, so to spec vert reinf spacing that works for both I'll do bars @24" o.c. Assuming that my statement above is correct, reinf between blocks, then these lower 2 courses would not be running bond but a series of blocks stacked 2 high with reinf between each adjacent stack.
- looks like typ 9ga horizontal reinf isn't used, so no horizontal reinf until above the 2 courses where I start my typ CMU.

Does the above sound correct?

 

[masonrygeek]

AAC block are cored (circular cores) that can be reinforced. Check with the manufacturer to check their coring pattern. Here is some general information on AAC:

https://www.cement.org/cement-concr...s-for-every-need/autoclaved-aerated-concrete.

AAC block is a thin bed mortar and don't typically use horizontal joint reinforcement. Bond beams are more common - again check with manufacturer for the availability of specialty units. Not sure why you would transition to regular block since AAC can be used in loadbearing and reinforced masonry.