Bamboo Mesh

[seedy]

BIL doing some Reno's for us, including a carport.

Asked when steel was delivered why no mesh came for the floor slab. Was told they will split bamboo and make a mesh from that. Secure the joints with stainless staples.

Questioned if it will rot the bamboo. Was told they have broken up old concrete slabs, 20 years old. Those with steel mesh had rusted to almost nothing, the bamboo was still green.

What would Asia do without bamboo !!!

[wayned]

I used steel and steel mesh in my house and bamboo in the carport and my outbuildings. I've had no problems. Bamboo was actually used for concrete reinforcement during WWII when all of the steel was being "weaponized"!

[StefanBBK]

I have seen bamboo used for little concrete plates etc.

Larger slabs I've seen only with steel. Ready nets are inexpensive.

Have broken up some old concrete and steel nets were in good condition still.

Guess one may be as good as the other. I stick with steel.

[eyecatcher]

To me its a no brainer these days its 20bt/m2.

Why waste time and effort to have something made that you are obviously unsure about.

[sometimewoodworker]

There are reports of bamboo renforcing having rotted within 7 years

YMMV

[IMHO]

One of the many beautiful synergies between concrete and steel is that that high pH of the cement stops rust.

If someone digs up a rebar reinforced slab and finds heavily rusted rebar inside, either:

1) It was that rusty to begin with

2) The cement wasn't mixed properly

3) The rebar was positioned too close to the edge of the cement (e.g. no standoffs/rocks used to lift it from the dirt)

4) The concrete is just too thin

5) The concrete is cracked in several places, allowing water to come in contact with the rebar

6) Any combination of the above.

Done properly, it'll have a service life of at least 50 years though.

[eyecatcher]

Yes you completely covered that IMHO......then again the reasons you list are exactly why the lazy buggers want to throw in bamboo.

[sometimewoodworker]

Janssen (1991) commented that the real problem in bamboo reinforced concrete is in the bonding between the bamboo and the concrete, which is never a problem with steel reinforcement. Concrete will shrink during the hardening process and these results in a firm bond of the concrete around the steel reinforcing bars while bamboo will absorb water as soon as the concrete is poured around it. During concrete hardening, bamboo will dry as well and shrink. The shrinkage of bamboo can be four times that of concrete. Clearly, this will completely break down any bonding between bamboo and concrete. This condition limits performance of the composite structure to a point far less than the yield strength of the individual materials of the composite.

[canopy]

Anyone using bamboo for rebar needs to be extremely aware of a vast array of considerations or it will be a failure. Even things as benign as the orientation of the bamboo is important. All such issues can be abated by making proper adjustments. But you need to know the potential problems and precautions. So take for example expansion: (1) the bamboo should be properly dried before use so it is totally shrunk for good lockage, (2) the bamboo should be properly coated so it does not soak up water in the mix and (3) the concrete mix should have minimal water added and be quick setting. Notice with those last two items not only shrinkage here, but also expansion that is a problem. You need to assure your bamboo does not get wet as the concrete cures and swell up because it will crack the concrete! This is just one small sample among a vast number of issues. I've used both steel and bamboo. My two cents is if you want to spend a lot of time researching and are a meticulous type of person, only then bamboo may be for you. For the average joe, stick to steel--even though it's seldom done right, it's far more forgiving than bamboo.