|Title||Geopolymer-based smart adhesives for infrastructure health monitoring: concept and feasibility|
|Publication Type||Journal Article|
|Year of Publication||2011|
|Authors||He J, Zhang G, Hou S, Cai C.S.|
|Journal||Journal of Transportation Research Board|
|Keywords||Adhesives, Cracking, Fiber optics, Geopolymer, infrastructure, Monitoring, Strain|
This paper describes the initial efforts to explore a new application of metakaolin-based geopolymers to structural health monitoring. A distributed geopolymer-fiber optic sensing (G-FOS) system is proposed, where geopolymers are used as smart adhesives to affix optical fibers to existing in-service structures to form an integrated G-FOS sensor. Results of feasibility testing in the laboratory indicated that the tensile cracking strain of geopolymers can be controlled by finely tuning the Si/Al ratios or adding appropriate aggregate fillers such as sand, thus rendering the “smart” nature of geopolymers for deformation-based sensing. Geopolymers with SiO2/Al2O3SiO2/Al2O3 ratios ⩾3.8⩾3.8 are viable adhesives that can develop strong bond to concrete, steel, and glass fiber. Laboratory prototype testing on steel specimens under uniaxial tension and on concrete beams under four-point bending validated the concept and feasibility of the proposed G-FOS system for structural health monitoring. It further demonstrated that the G-FOS system cannot only detect overstraining events in steel but also measure the crack size in concrete.