Development of a triboluminescence-based sensor system for concrete structures

Abstract

The triboluminescence phenomenon has been proposed as a sensor system for detecting and monitoring damage in aerospace and civil infrastructure systems (CIS). While significant work is being done in developing such systems for aerospace structures, little or no work is being done in developing triboluminescence-based sensor systems for the critical and aging CIS. This article reports some findings in the work being done by the authors to develop such a sensor system for civil infrastructure applications. A ZnS:Mn-based cementitious patch that emits light when stressed or fractured was developed and its triboluminescence performance under loading characterized. The results show that a ZnS:Mn concentration level of 10% gives the best triboluminescence response without adversely affecting the compressive strength of the patch, while also minimizing the use of the expensive ZnS:Mn crystals. The triboluminescence response increased as the concentration of ZnS:Mn in the system increased. The highest triboluminescence response was obtained at a concentration level of 25% but resulted in significant reduction in the system’s compressive strength. Nonetheless, the presence of ZnS:Mn affects the hydration process by slowing down the conversion of the needle-shaped crystals of calcium sulfoaluminate hydrate (ettringites) into the monosulfate hydrate that makes concrete vulnerable to sulfate attack.