New Concrete Structure Reinforcement Technology Edging Towards Commercial Viability

Copyright Shimizu Corp.

Shimizu Corp., a major Japanese construction company, the National Defense Academy of Japan, and Mitsui Chemicals Industrial Products Ltd., announced on September 27, 2012, that their new structure reinforcement technology is now approaching practical use. The new technology, called Toughness Coat, is a thin coating of polyurea resin applied to the concrete structure surface, dramatically improving its deformation performance. Structural reinforcement work using this technology could reduce construction costs by about 50% and construction time by about 80% compared to conventional methods.

In addition to its high durability, which makes the polyurea resin an effective water-proofing and surface protection material for structures, it also has a notable characteristic of returning nearly to its original shape without severe fracturing after being stretched to about twice its original size. Having recognized this stretching/restoring property, the three parties conducted various performance experiments on concrete structures coated with polyurea resin. Load tests and impact tests conducted at the National Defense Academy of Japan on structural specimens with 2mm-thick polyurea coating verified that the coating makes structural assemblies support loads with a tenacity resembling rubber, and allows them to withstand major deformations that, without the coating, could fracture them.

Polyurea coating hardens in a few minutes after application and its reinforcing effect develops in a few hours. The new reinforcement technology using polyurea coating opens up the possibility for making existing structures more tenacious and fracture-resistant, and the three parties intend to continue collecting necessary data to establish detailed design methods using the coating.