Concrete is not only serve as a structure, it can also have added function if we re-engineered material in concrete. One of them is concrete as well as sensor called smart concrete. Smart concrete is impregnated with carbon fibers in the matrix. Carbon fibers as reinforcement in addition to serve as sensors in the concrete itself so it don’t need another sensors. Carbon fibers are used only in small amounts is less than 10 vol% matrix.
The principle of this carbon fiber works in piezoresistivity which respond the mechanical changes (stress and strain) in the form of electrical impulses. Basically, concrete has conductive properties, but to increase the sensitivity stress and strain changes, we need a high conductive material. Therefore we need a material which has a large conductivity value or relatively small resistance value, one of which is carbon fiber, so if there are changes in stress and strain of the additional load will be monitored more sensitively from the change of resistance value. It is reversible for elastic deformation, and irreversible for inelastic deformation or cracking (fracture). The electrical conductivity of carbon fiber is very important in smart concrete structures. This can be influenced by variations in composition and type of carbon fiber used to be able to respond elastic or inelastic deformation of concrete structures properly. The materials used in concrete mix design followed by the power of K-450 to Highway or Rigid Pavement. The addition of carbon fiber is a synthetic polymer of polyacrylonitrile (PAN) in the form of chopped. Techniques for distribute carbon fibers to concrete is a determinant in the success of concrete technology with carbon fiber reinforcement.
Sensitivity Resistance change is influenced by the bond between carbon fiber and concrete matrix itself. Concrete material bonds have many determinants that in making these things must be considered. Selection of appropriate ingredients and mixing techniques are workable and measurable can give a good bond between the material in concrete. By comparing the sensitivity of smart concrete with carbon fiber composition by 0.3%, 0.4% and 0.5% found that the result for more carbon fiber composition, the resistivity of the concrete will be more sensitive but its strength should be reviewed again if the structural strength standards for Rigid pavement.
