Performance of cementitious composites incorporating ground TFT-LCD waste glass

In South Korea, a great amount of thin-film transistor liquid-crystal display (TFT-LCD) waste glass in the form of industrial waste has been produced during the electronic equipment manufacturing process in recent years. This paper presents a detailed experimental study on the performance of mortar specimens replaced partially by TFT-LCD waste glass (TLWG). The replacement level of TLWG was the main test variable. Setting time, compressive and flexural strengths, drying shrinkage, and chloride-ion permeability tests of mortar specimens incorporating TLWG were carried out to evaluate the possibility of recycling TLWG as a cementitious material. In addition, field-emission scanning electron microscope (FE-SEM) investigations were used to observe the effect of TLWG replacement on the microstructural changes of paste samples. From the test results, it was found that higher replacement levels of TLWG (above 20 %) negatively affected the strength, drying shrinkage, and chloride-ion penetrability of mortar specimens because it led to a porous structure in the hardened cement system. On the other hand, because of the pozzolanic activity, the use of TLWG up to a maximum 10 % replacement level was possibly effective in enhancing mechanical properties of mortars. This was verified through the microstructural observations by SEM and energy dispersive spectroscopy (EDS) analysis. Hence, taking into consideration economical and mechanical factors, it can be concluded that appropriate replacement of TLWG as a cementitious material holds promise in the production of concrete, as well as in recycling industrial waste.