Abstract:
Carbon based nano-materials are quickly becoming the most promising nanomaterials in construction industry because of their unique mechanical and electrical properties. In this research, graphitic nano/micro platelets (GNMPs) were added in cement mortar. Because of nano-scale size of GNMPs, they can be distributed on a nano-scale than commonly used micro-reinforcing fibers. As a result, microcracks are interrupted much more quickly during propagation in a nano-reinforced matrix and thereby enhance the ductility and fracture toughness of the resultant matrix. To study this property, 28 days cured nano-reinforced mortar specimens were tested under strain controlled Universal Testing Machine (UTM) at a very sensitive state rate of around 0.005mm/min. Test results reveal that the strength, ductility, and fracture toughness can be improved with the addition of GNMPs. A scanning electron microscope (SEM) is used to verify the involved strengthening mechanisms encompassing crack bridging and crack branching effects of inducted GNMPs. Electrically conductive smart cement sensors were developed by intrusions of GNMPs with an ability to detect measurable change in resistivity under compressive loading. For experimental determination of percolation threshold four-probe test was performed. Experimental values were in the coherence with theoretical values calculated using Celzard Approach. The experimental values pertaining to fracture mechanics were further numerically validated using ANSYS and the results were found well in agreement to one another
