Production of glass-alkali binder for construction purposes by recycling of cullet
Municipal solid waste poses significant environmental challenges due to its wide range and potential contaminating impact. Finding sustainable solutions for its disposal is imperative. Moreover, certain types of municipal solid waste can serve as valuable resources in the construction sector. This study introduces a novel non-firing binder, devoid of cement, crafted from cullet, caustic alkali, water, and a plasticizing additive. These constituents undergo collaborative wet grinding in a ball mill, achieving a specific surface area of 500−550 m2/kg. Concurrently during milling, glass particles are ground, and amorphous silica is leached with an alkaline solution, yielding a viscous-fluid adhesive mass enriched with siliceous compounds. This mass fills metal mold cells; upon attaining stripping strength, samples undergo heat treatment (drying) up to 90ºC. During this process, sols transform into polysilicic acid gels, which, after 5−6 hours, partially crystallize, achieving requisite strength. The resulting binder, produced without firing, boasts a compressive strength of approximately 25 MPa and a water resistance coefficient of 0.89. Suitable for low-grade concrete production (including glass concrete, fine-grained concrete, and foam concrete), its microstructure was analyzed via scanning electron microscopy, affirming the effective utilization of cullet in construction materials.