Workability, compressive strength, and microstructures of one-part rubberized geopolymer mortar

Rubberized geopolymers are attracting attention as solutions to ecological issues caused by increased production of industrial waste and used tires. However, the inconvenience of handling alkaline solutions limits the use of conventional two-part geopolymer materials. Therefore, a onepart rubberized geopolymer mortar (ORGM) activated by a solid alkali activator was developed in this study. An experimental investigation was conducted on the setting time, fluidity, density, and compressive strength, of the ORGM, and the test findings were compared with two-part rubberized geopolymer mortar (TRGM). In addition, the cost efficiency and environmental impact of the rubberized geopolymer mortars (RGMs) were evaluated. The results showed that the ORGM activated by anhydrous Na2SiO3 powder (ORGM-NS) had superior economic and environmental benefits compared with ordinary Portland cement mortar. Although the addition of rubber reduced the compressive strength, the ORGM-NS with a 10% rubber content still displayed a 28-d compressive strength of 40.7 MPa, which was approximately 170% higher than those activated by NaOH powder combined with instant Na2SiO3 powder (ORGM-NH). Compared with TRGM, the ORGM has a similar functional cost, a more convenient preparation method and a slower polymerization process.