Title: Development and Characterization of a Tension-Hardening Quarry Waste-Based Geopolymer Concrete

Author(s): Zoi G. Ralli and Stavroula J. Pantazopoulou

Publication: Materials Journal

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Keywords: CO₂ emissions; DIC; durability; ductility; geopolymer concrete; Metagabbro powder; steel fibers; strain-hardening; tension-hardening

DOI: 10.14359/51740704

Date: 3/15/2024

Abstract:
In light of the effort for decarbonization of the energy sector, it is believed that common geopolymer binding materials such as fly ash may eventually become scarce, and new geological aluminosilicate materials should be explored as alternative binders in geopolymer concrete. A novel, tension-hardening geopolymer concrete (THGC) that incorporates high amounts of semi-reactive quarry wastes (Metagabbro) as a precursor and coarse quarry sand (granite) was developed in this study using geopolymer formulations. The material was optimized based on the particle packing theory and was characterized in terms of mechanical, physical, and durability properties (i.e., compressive, tensile, flexural resistance, Young’s Modulus, Poisson’s ratio; absorption, drying shrinkage, abrasion, and coefficient of thermal expansion; chloride ion penetration, sulfate, and salt-scaling resistance). The developed THGC with an air-dry density of 1,940 kg/m³ [121 lb/ft³], incorporates short steel fibers at a volume ratio of 2% and is highly ductile in both uniaxial tension and compression (uniaxial tensile strain capacity of 0.6% at an 80% post-peak residual tensile strength). Using DIC, multiple crack formation was observed in the strain-hardening phase of the tension response. In compression the material maintained its integrity beyond the peak load, having attained 1.8% compressive strain at 80% post-peak residual strength whereas upon further reduction to 50% residual strength, the sustained axial and lateral strains were 2.5% and 3.5%, respectively. The material exhibited low permeability to chloride ions and significant abrasion resistance due to the high contents of Metagabbro powder and granite sand. The enhanced properties of the material, combined with the complete elimination of ordinary Portland cement from the mix, hold promise for the development of sustainable and resilient structural materials with low CO₂j, emissions while also enabling the innovative disposal of wastes as active binding components.