Incorporating Liquid Crystal Display (LCD) Glass Waste as Supplementary Cementing Material (SCM) in Cement Mortars—Rationale Based on Hydration, Durability, and Pore Characteristics

Abstract

This paper assesses the feasibility of using liquid crystal display (LCD) waste glass as a supplementary cementing material in cement mortars. Two different sizes of LCD waste glass powder (LGP) particles were used (5 µm and 12 µm) with two substitution levels with cement in mortar (10% and 20%). The resulting mortars were evaluated for strength, hydration, porosity and durability through various experimental techniques. It was found that LGP particles lead to appreciable strength gain at all ages in comparison with control mortar, especially significant strength gain of 18% was observed at 28-day. This is attributed to the greater gel-space ratio as corroborated by the experimental determination of porosity, which is found less for LGP-incorporated mortars as compared to control cement mortar. The smaller particle size of LGPs not only accelerates the pozzolanic reaction in alkaline cementitious matrix, but also fills the smaller pores, thus reducing porosity and contributing to strength gain. Increased hydration was also elucidated qualitatively by backscattered electron imaging. Due to the increased hydration in LGP-incorporated pastes and mortars, the durability (in terms of chloride ion permeability) has also been found improved. Thus, it is established that 10% (by weight) of cement can be replaced with 12 μm LGP, whereas 20% can be replaced with 5 μm LDP for improved strength and durability. Incorporating LCD waste in mortars and concretes as partial replacement of cement can not only help utilize this potentially hazardous waste, but also significantly reduce the associated carbon dioxide emissions, thus promoting sustainable development.

Roles of Waste Glass and the Effect of Process Parameters on the Properties of Sustainable Cement and Geopolymer Concrete—A State-of-the-Art Review

“…Finer WG powder (particles < 150 µm) shows better pozzolanic reactivity and filler effect, thus helping to produce more C-S-H products and a dense microstructure while developing more strength [79]. Kim et al [80] observed approximately 22% and 11% improvement in mortar compressive strength after replacing 10% cement with WG powder of 5 µm and 12 µm particle size, respectively. Omran and Tagnit-Hamou [81] reported a 35% improvement in the splitting tensile strength of concrete at the 28-day curing age when WG powder (particle size < 40 µm) was used to replace 20% cement.…”

High Sulfate Attack Resistance of Reinforced Concrete Flumes Containing Liquid Crystal Display (LCD) Waste Glass Powder

“…The LCD cement showed compressive strengths slightly smaller for the diameter of 12 μm; however, the compressive strengths were higher for cement with a 5 μm diameter (Figure 6). This phenomenon may be caused by the fact that the Si and Al ions in the LWGP reacted with the Ca ions, which were included in the pore solution, to form the C–S–H and C–A–H gels, thus producing a dense and more compact matrix [13].…”

“…OPC and two different types of LWGP were used as the primary binder in this experimental study. LWGP were prepared by grinding the LCD glass [13]. Table 1 shows the chemical properties of OPC and LWGP.…”

“…The replacement dosage of cement and the high fineness of the LCD waste glass powder (LWGP) are considered appropriate for durability improvement. Although the substitution of cement with LWGP improves durability as well as mechanical and microstructural properties, the deterministic characteristics of LCD glass powder particles include particle size/surface area and the substitution amount [13,14,15,16,17,18].…”

Utilization of By-Products and Wastes as Supplementary Cementitious Materials in Structural Mortar for Sustainable Construction

“…In 2001, the amount of nonrecyclable waste glass that went into landfills in the UK was about 1.65 million tons [115]. In 2015, Korea alone produced 40,000 tons of waste of Liquid Crystal Display (LCD) glass panels [116]. Although waste glass powder (WGP) can be categorized as a pozzolanic-cementitious material according to ASTM C618, the risk of alkali-silica reaction (ASR) has limited its use in cement-based materials [84,115,117].…”