Study ‘cracks’ mystery of water-promoted fracture growth on glassGlass windows o
Study ‘cracks’ mystery of water-promoted fracture growth on glass
Glass windows often endure external environmental factors such as wind, rain, and humidity, which lead to the formation of microcracks in their surface. For instance, a gust of wind can propel sand onto a window and create microscale surface cracks due to the impact of sharp-edged sand particles. These microcracks then grow in size when aggravated by water droplets and humidity.
When water comes in contact with these surface flaws, it penetrates the microcracks and slowly dissolves the silicon-oxygen bonds. This chemical attack breaks the glass networks which gradually degrades the mechanical strength and optical properties of glass structures. This environmentally enhanced crack growth process is known as stress corrosion or subcritical crack growth (SCG). The depreciation of mechanical performance due to SCG raises safety concerns for skyscrapers and high-rise buildings.
Recently, scientists have taken an interest in the effect of SCG on two widely used types of soda-lime glass: annealed and tempered glass. However, most studies have focused on establishing crack growth rates, and not much is known about the effect of water on the propagation of crack flaws. Additionally, many of the studies investigated the microcrack propagation dynamics of annealed glass and not tempered glass.
