Japan: Development of Anti-seismic Concrete with Plastic Fiber

< P > < FONT face = Verdana > Japan's Disaster Prevention Science and Technology Research Institute, in cooperation with Tokyo Institute of Technology, has made a new type of concrete by replacing gravel in building materials with plastic fibers. Experiments show that the pier model made of this concrete can resist 1.5 times the shaking of the Great Hanshin Earthquake in 1995.

< P > < FONT face = Verdana > Ordinary concrete is made by mixing cement with sand and gravel. Professor Kazuhiko Kawashima of Tokyo Institute of Technology and others reported that they made polypropylene, the raw material of household plastic storage boxes, into fibers with a length of 1.2 cm and a section width of 0.03 mm, and mixed it into concrete in a proportion of 1.5% to build a pier model with the same volume as the real one, with a height of 7.5 m and a section width of 1.8 m.

< P > < FONT face = Verdana > Since then, Kazuhiko Kawashima and the researchers of Japan Disaster Prevention Science and Technology Research Institute have conducted three experiments on the pier model with the same shaking intensity as the Great Hanshin Earthquake, and then increased the shaking intensity of the shaking table to 1.5 times that of the earthquake for three experiments. It was found that there was no other damage except 10 small cracks on the pier model. Experts believe that this is because after mixing polypropylene fibers, the toughness of concrete increases, thus increasing the tensile strength.

< P > < FONT face = Verdana > Kazuhiko Kawashima pointed out that in the Great Hanshin Earthquake, some viaducts of the expressway overturned, and if the viaduct construction materials are made with the above technology, it is expected to improve the seismic strength. As for the problem that this new technology may lead to higher cost, Kawashima believes that as long as mass production is achieved, the cost can be reduced, and if the bridge built in this way does not collapse in a major earthquake, it will avoid major losses.

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