Strength Development Characteristics of Concrete Replaced with Different Waste Glasses from Display Industry as a Cementitious Material

In this study, the fundamental and mineralogical properties of the binary system incorporating the industrial display byproducts, liquid crystal display (LCD) and organic light emitting diodes (OLED), as a cementitious material. A substitution level of the fine glass powders, and water to binder ratio were kept at 30% and 0.4 for all mixes, respectively. Strength development for the blended concretes was monitored until 91 days of curing, during which a modification of pore distribution was examined by mercury intrusion porosimetry. Simultaneously, the pozzolanic activity was evaluated by the content of calcium hydroxide (CH) in the cement pastes obtained from results of thermogravimetry analysis, and the phase composition of the specimens was quantitatively determined X-ray diffraction with Rietveld refinement method. As a result, the CH content in the glass-mixed specimen was decreased with time after certain age depending on glass types. Also, OLED was much effective to the pozzolanic activity, producing a higher content of C-S-H gel at 91 days, compared to LCD. This phenomenon may be attributed to a difference of Al2O3 and SiO2 content in the oxide composition, which would induce a shift of larger pore to micropore resulting in an increase in the strength for OLED concrete.