Bamboo is not stronger than steel reinforcement, steel and concrete are bonded to each other, so after all inventions steel is best material for reinforcement for concrete
Bamboo as Concrete Reinforcement
Yes Bamboo can be used and it has been in use previously. Wood is also strong in tension and bamboo has a lot of tensile strength. Following are some points to be considered for using bamboo in concrete.
Factors to be considered for using bamboo as Concrete reinforcement
The following factors should be considered in the selection of bamboo culms (whole plants) for use as reinforcement in concrete structures:
- Use only bamboo showing a pronounced brown color. This will insure that the plant is at least three years old.
- Select the longest large diameter culms available.
- Do not use whole culms of green, unseasoned bamboo.
- Avoid bamboo cut in spring or early summer. These culms are generally weaker due to increased fiber moisture content.
The same mix designs can be used as would normally be used with steel reinforced concrete. Concrete slump should be as low as workability will allow. Excess water causes swelling of the bamboo. High early-strength cement is preferred to minimize cracks caused by swelling of bamboo when seasoned bamboo cannot be waterproofed.
Design & construction Principles
Bamboo reinforcement should not be placed less than 1-1/2 inches from the face of the concrete surface. When using whole culms, the top and bottom of the stems should be alternated in every row and the nodes or collars, should be staggered. This will insure a fairly uniform cross section of the bamboo throughout the length of the member, and the wedging effect obtained at the nodes will materially increase the bond between concrete and bamboo.
The clear spacing between bamboo rods or splints should not be less than the maximum size aggregate plus 1/4 inch. Reinforcement should be evenly spaced and lashed together on short sticks placed at right angles to the main reinforcement. When more than one layer is required, the layers should also be tied together. Ties should preferably be made with wire in important members. For secondary members, ties can be made with vegetation strips.
Bamboo must be securely tied down before placing the concrete. It should be fixed at regular intervals of 3 to 4 feet to prevent it from floating up in the concrete during placement and vibration. In flexural members continuous, one-half to two-thirds of the bottom longitudinal reinforcement should be bent up near the supports. This is especially recommended in members continuous over several supports. Additional diagonal tension reinforcement in the form of stirrups must be used near the supports. The vertical stirrups can be made from wire or packing case straps when available; they can also be improvised from split sections of bamboo bent into U-shape, and tied securely to both bottom longitudinal reinforcement and bent-up reinforcement. Spacing of the stirrups should not exceed 6 inches.
Table I. Mechanical properties of bamboo reinforcement
|Ultimate compressive strength|| |
|Allowable compressive stress||s|
|Ultimate tensile strength|| |
|Allowable tensile stress||s|
|Allowable bond stress||u|
|Modulus of elasticity||E|
Bamboo As The Building Material
More related Links
http://www.bambubrasileiro.com/arquivos/Bamboo Reinforcement Concrete - Ghavami - 2004.pdf