Effect of Nano-SiO2 on ITZ Cracks of Concrete

The traditional picture of the interfacial transition zone (ITZ) in concrete involves an approximately 30 μm zone around each aggregate, within which the porosity increases as the aggregate interface is approached. The ITZ microcracks in concrete will grows to visible cracks, thus they are very important to be studied. Effect of nano-SiO2 on cracks width in ITZ was studied in this research. For investigation of crack width, SE signals of SEM were used. The samples were cut from edges and middle of 5×5×5 cm cubic specimens. It was seen that nano-SiO2 could less the crack width. It is for the first time that SE use for ITZ imaging. Finally it was shown that adding nano-SiO2 could reduce the width of ITZ cracks.