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Bamboo Reinforced Concrete

Introduction

  • 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.

Preparation

  • Sizing
  • Splitting
  • Seasoning
  • Bending
  • 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

  • Durability
  • 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.

Conclusion

  • 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.

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