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Japan Trying to Revive Bamboo-Reinforced Concrete

Yomiuri Shimbun file photo
Bamboo forest

Fukushima, Dec. 31 (Jiji Press)—A group in the Tohoku northeastern Japan region is trying to revive a prewar technology using bamboo to create reinforcement frameworks for concrete instead of steel materials.

Bamboo-reinforced concrete is drawing attention not only as an alternative building material but as a potential solution to a key problem with bamboo forests, which tend to make the grounds vulnerable to landslides.

In order to make bamboo-reinforced concrete, bamboo is processed into strips, which are then assembled into grids to form frameworks.

Bamboo materials were used to reinforce concrete in Japan for decades until the early Showa period in the early 20th century because steel was in short supply due to wars.

Some of the structures built with bamboo-reinforced concrete still exist, including the Chojataki bridge in Ichinoseki in the Tohoku prefecture of Iwate.

The Tohoku group is aiming to put bamboo-reinforced concrete back into practical use by consulting documents from the time. Its members are Nihon University, Tohoku University and five companies in the Tohoku prefectures of Yamagata and Fukushima.

Bamboo grows quickly, causing damage to nearby houses, and expands widely and shallowly, making ground more prone to landslides. Meanwhile, the plant is easy to process.

“We wanted to make use of it as a construction material,” said Akihiko Takahashi, head of the planning and technology division of Yamagata construction consultancy Shinwa Sekkei, a member of the group.

The group created prototypes of bamboo-reinforced concrete and repeatedly checked their strength. In June 2023, it confirmed that its bamboo-reinforced concrete is strong enough to meet Japanese Industrial Standards.

“As a result of repeated trial and error, we were able to secure strength comparable with that of reinforced concrete by scraping the inner side of bamboo strips, which is weak,” said professor Yasuhiro Koda of Nihon University’s College of Engineering, involved in the prototype production.

On Nov. 26, 2023, a demonstration test toward commercialization began in Minamiaizu, Fukushima. A drainage ditch about 70 meters long made with bamboo-reinforced concrete was installed in a fallow field. Its durability will be examined through continuous use.

Although there are problems such as how to ensure a stable supply of bamboo materials, Koda said, “We aim to realize the widespread use of bamboo-reinforced concrete in infrastructure facilities familiar to many people.”