Abstract
Carbon fibers are excellent mixing materials for mortar or concrete because they can prevent the generation of fracture inside the material. Carbon fibers have low specific gravity, high strength, and high elastic modulus; further, they are inert to many chemical substances and also have excellent heat resistance. For these reasons, carbon fibers can be used as excellent mixing materials for mortar or concrete.
This study was initially started for the purpose of preventing the collapse of houses during the Great Hanshin-Awaji Earthquake; however, at present, it is also aimed at countering the effects of the Niigata Earthquake.
Carbon fiber reinforced plastics (CFRP) are currently being used as structural materials in aircrafts, automobiles, etc., and will be discarded in large quantities as scrap. Hence, the objective of this study also includes the development of a breakthrough approach for recycling scrap CFRPs for application as mixing materials in concrete or mortar. Through this study, two new materials have been developed. The first material is carbon fiber reinforced mortar-A (CFRM-A) in which polyacrylonitrile (PAN) fiber is mixed into mortar; the second material is CFRM-B in which chopped CFRPs are mixed with CFRM-A. The fractural strength and elastic modulus of these materials have been measured. The results show that CFRM-B has sufficient capacity to be applied to the construction of earthquake-resistant structures. In addition, the fundamental experiments on the heat treatment of CFRPs are performed and the carbon fibers are extracted.
A mass loss occurs in CFRPs at approximately 700 K; this becomes constant at approximately 30% above 1000 K. This loss is mainly generated by the thermal decomposition of the resin in CFRP. The activation temperature of CFRPs was estimated in this study. Therefore, the estimation of the mass loss in CFRP became possible.
