APPLICATIONS

Carbon fiber reinforced concrete (CFRC) had perhaps seen the most extensive application and acceptance in Japan between 1986 and 1993 due to the prevailing need for lighter and tougher panels for seismic resistance in building construction. However, a distinction needs to be made between two forms of CFCC that are normally lumped into a single category. Most lists combine quantities made of continuous fiber reinforced concrete (using carbon strands or 3D grids) with CFCC.

In a number of cases, lumping the two categories together significantly inflated the actual usage of short fiber reinforcement in concrete. This section will be restricted to the use of chopped or short fibers only. Within this context, the dominant application seems to be precast curtain walls. Other applications such as interior walls, coatings and architectural facades are far behind. Examples of the use of CFCC in a number of buildings since 1988 are listed in Table 2.6. The first large scale application of CFRC was in the construction of the Al-Shaheed monument in Iraq in 1984 by the Kajima Co.

Figure 2.2 shows an example of the use of CFRC panels for complicated aesthetic design features at the Kita Kyusho Prince Hotel. The Ark Mori Building in Tokyo, built in 1986 using chopped carbon fiber in curtain walls, includes 32,000 m² of wall panels prefabricated of CFRC (5,500 panels) using 170,000 kg (170 metric tons) of chopped carbon fiber. The dimensions of each panel were 1.47 m by 3.76 m. The specific gravity of the resulting panels was about 1.3 as compared to 1.85 if the carbon fiber had not been used. It is estimated that reducing the dead load by using these panels resulted in over a 20% reduction in the weight of the steel framing required to hold them. The overall reduction of dead load of the supporting elements (beams, columns and foundations) was also significant. A slightly different scheme was used for the Tokyo Dental College Building, which was constructed using a steel frame with thin CFRC curtain walls between the channels of the frame. This approach enabled rapid construction of the building. The panels, which were prefabricated using steam for curing, were rated for fire resistance at 1 hour for a 50 mm thickness and 30 minutes for a 30 mm thickness. The wind resistance rating was 280 kgf/m², compared to 630 kgf/m² for panels used in the Ark Mori Building.

Fig. 2.2. Use of CFRC panels in the Kita Kyusho Prince Hotel.