Why Do Builders Place Plastic Bottles Inside Concrete Pillars? Here's the Reason
The simple construction trick helps improve the bond between concrete layers, making pillars stronger and more durable.
New Delhi: It may look unusual, but some builders temporarily place a plastic bottle inside a concrete pillar during construction. Far from being a shortcut, the technique is used to improve the strength of reinforced concrete (RCC) columns.
When a pillar is cast in stages rather than in a single pour, workers place a plastic bottle in the fresh concrete and remove it after the mix hardens. The resulting cavity is later filled with fresh concrete, creating a mechanical interlock between the old and new layers. This helps the two concrete sections bond more effectively, reducing the risk of weak joints and improving the pillar's durability.
Apart from this technique, steel reinforcement bars (rebars) and stirrups are used to provide structural strength and keep the reinforcement securely in place. Builders also use concrete vibrators to remove trapped air pockets, ensuring the concrete is dense and evenly compacted.
Experts recommend casting an entire storey's pillar in one continuous pour whenever possible to avoid cold joints, which can weaken the structure. If construction is carried out in phases, reinforcement bars are left exposed so the next layer can bond properly.
Another critical step is curing. After the pillar is cast, it is kept moist by regularly sprinkling water or covering it with wet sacks. Proper curing allows the cement to hydrate fully, increasing strength and reducing the chances of cracking.
Although the plastic bottle is only a temporary tool, it helps improve the connection between concrete layers, contributing to a stronger and longer-lasting pillar.
Disclaimer: The information provided in this article is for general informational purposes only. While we endeavor to keep the information up to date and correct, News Setu makes no representations or warranties of any kind, express or implied, about the completeness, accuracy, or reliability of the content. Any reliance you place on such information is strictly at your own risk.