Paul,
Anything you place in a joint will require inspection and periodic maintenance. Anything requiring periodic maintenance will likely be ignored.
I would suggest post tensioning using bonded encapsulated strand. You can design the top concrete to be in compression and the strand would be protected from corrosion by the encapsulation. I do not like to rely on admixtures for corrosion resistance. If you want a more definitive mix for corrosion resistance, consider using SCC.
http://www.selfconsolidatingconcrete.org/
You will get very low w/c ratios and high strength. As a minimum use epoxy coated rebar.
This is a site for bonded encapsulated strand by VSL.
http://www.vsl.net/SYSTEMSPRODUCTS/VSLABBONDEDSLABS/tabid/90/Default.aspx
You might also consider a ribbed structure like joist or skip joist to reduce weight and increase stiffness. A post tensioned ribbed structure might be your best bet. I would still urge you to consider the bonded PT. Call the PTI. http://www.post-tensioning.org/ They can give you sound advice and help with a preliminary design.
Regards, Harold Sprague
From: PFFEI@aol.com
Date: Fri, 14 Oct 2011 09:04:40 -0400
Subject: cantilver conc balcony
To: seaint@seaint.org
Anything you place in a joint will require inspection and periodic maintenance. Anything requiring periodic maintenance will likely be ignored.
I would suggest post tensioning using bonded encapsulated strand. You can design the top concrete to be in compression and the strand would be protected from corrosion by the encapsulation. I do not like to rely on admixtures for corrosion resistance. If you want a more definitive mix for corrosion resistance, consider using SCC.
http://www.selfconsolidatingconcrete.org/
You will get very low w/c ratios and high strength. As a minimum use epoxy coated rebar.
This is a site for bonded encapsulated strand by VSL.
http://www.vsl.net/SYSTEMSPRODUCTS/VSLABBONDEDSLABS/tabid/90/Default.aspx
You might also consider a ribbed structure like joist or skip joist to reduce weight and increase stiffness. A post tensioned ribbed structure might be your best bet. I would still urge you to consider the bonded PT. Call the PTI. http://www.post-tensioning.org/ They can give you sound advice and help with a preliminary design.
Regards, Harold Sprague
From: PFFEI@aol.com
Date: Fri, 14 Oct 2011 09:04:40 -0400
Subject: cantilver conc balcony
To: seaint@seaint.org
I have an exterior concrete balcony with a 15' cantilever and 10' backspan. I expect that no matter how thick I make slab I will get deflection and a crack over the support. would it be best to detail a pour joint over the support or cut a crack control joint to control the crack? joint could be filled with caulk / flexible joint sealer.
Also, project is located on a bluff about 1/2 mile away and 300' above the ocean (Malibu). For slab exposed as finish, is anything recommend fro rebar protection? I was thinking 4000 psi conc with w/c = 0.5 max, and 2" cover. should I include something like xypex in the mix, or increase rebar cover, or am I distant enough from ocean that salt will be a minor issue?
Thanks in advance,
Paul Franceschi