- Bamboo has been used as a construction material in certain area for centuries. A study of bamboo is used as a reinforcement in precast concrete elements was carried out in U.S. Army Engineer Waterway experiment station in 1964.
- Bamboo was given recent consideration for use as reinforcement in soil cement pavement slabs in which the slabs behave in elastically even under light loads.
- Bamboo is characterized as a bio degradable, renewable and an energy efficient natural resource.
- It is an environmentally sustainable building material.
- Bamboo can be used as an alternative material in reinforcement of concrete.
Characteristics of Bamboo Reinforced Concrete
- Bamboo can prevent pollution.
- The specific gravity of bamboo varies between 0.4 to 0.5
- The strength of bamboo is greater than most of the timber products.
- Bamboo is giant grass not a tree.
- The ratio of tensile strength to specific weight of the bamboo is about 6 times that of steel.
- The density of fibres in cross-section of a bamboo shell varies with thickness as well as height.
- Bamboo is more prone to insect attack than other trees and grasses.
Selection of Bamboo
- Use only bamboo showing a pronounced brown color. This will insure that the plant is at least three years old.
- 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.
- Select the longest large diameter culms available.
- Waterproof coating
Concrete Mix Proportions
- The same mix designs can be used as would normally be used with steel reinforced concrete.
- Excess water causes swelling of the bamboo.
- Concrete slump should not as low as workability will allow.
- High-early strength cement is preferred to minimize cracks caused by swelling of bamboo when seasoned bamboo cannot be waterproofed.
Bamboo as an Engineering material
- Effect of water absorption
- Bonding strength
Comparison of Steel and Bamboo
- The strength of bamboo is greater than steel.
- Increases the strength of the buildings.
- Bamboo can crack and deflect more than steel reinforcement.
- Bamboo is easily accessible.
- Bamboo lowers the cost of construction.
Placement of Bamboo
- Bamboo reinforcement should not be placed less than 1.5 inches from the face of the concrete surface.
- The clear spacing between bamboo rods or splints should be less than the maximum size aggregate plus ¼ inch.
- The ties can be made with vegetation strips.
- Spacing of the stirrups should not exceed 6 inches.
- Reinforcement should be evenly spaced and lashed together on short sticks placed at right angles to the main reinforcement.
Effect of water absorption
- The main shortcomings of bamboo is its property of water absorption.
- The dimensional variation of untreated bamboo due to water absorption can cause micro or even macro cracks in cured concrete.
- This can be controlled by treating the bamboo.
Advantages of Reinforced Bamboo Concrete
- Low cost construction.
- It is eco friendly as it absorbs NO2 in water and CO2 in air.
- Bamboo is easily accessible.
- It withstands 7.8 Richter of seismic attack.
- It is a boon for light weight and temporary buildings.
- The environmental and financial comparison demonstrates that bamboo can compete as a building material.
- Furthermore bamboo can play a role a finishing material.
- Bamboo is a natural product and will therefore always have some extent of irregularity.
- Bamboo can play a role as a non-supporting or finishing material.