Preparation and Characterization of Geopolymers Obtained from Alkaline Activated Hollow Brick Waste

Geopolymers are inorganic polymers obtained through the alkaline activation of aluminosilicates. Due to their cementitious properties, they are being studied as a sustainable alternative to Portland cement. Red ceramic waste (RCW), being a source of silica and alumina, can serve as a precursor for producing geopolymers. In this work, we evaluated the feasibility of producing geopolymers from hollow brick (HB) and hydrated lime, using only sodium hydroxide as an alkaline activator. The test specimens were prepared replacement HB by up to 30 wt% of hydrated lime, aiming to evaluate the compressive strength after 7 and 28 curing days of the geopolymer produced. The results showed that samples with 30 wt% of hydrated lime, achieved the highest compressive strength (11.26 MPa) after 28 days of curing, although all values found were above the limit established by Brazilian standards for modular geopolymer bricks. The results therefore show a sustainable and widely viable implementation alternative to reduce the environmental impacts caused by the production of Portland cement.