27 / 2022-03-10 15:38:09

Mechanical Performance of Geopolymer Aggregate Engineered Cementitious Composites: Influence of Aggregate Sizes

Engineered Cementitious Composites (ECC),Flaw effect,Geopolymer aggregates (GPA),Particle Size,Ultra-high strength

In this study, Engineered Cementitious Composites (ECC) with ultra-high strength and ductility were developed using artificial geopolymer aggregates (GPA), and the influence of GPA size (i.e., 0.3-0.6 mm, 0.6-1.18 mm, and 1.18-2.36 mm) on the mechanical performance of ECC was investigated. From the calorimetry test, it was found that GPA could react with the cementitious pastes, and the hydration heat became higher with the decrease of the GPA size. In addition, although the increase of GPA size resulted in a reduction of the compressive strength of GPA-ECC, the obtained values of all the mixes were above 145 MPa, which guaranteed the ultra-high strength nature of the produced ECC. Moreover, from direct tensile tests, GPA-ECC with the aggregate size of 0.3-0.6 mm showed the best performance with the highest tensile strength (over 15 MPa), tensile strain capacity (over 8%) and strain energy density (over 850 kJ/m³), and the increase of the aggregate size resulted in a reduction of the tensile performance of GPA-ECC. Furthermore, X-ray computed tomography (X-CT) demonstrated the flaw effect of the GPA in ECC. The findings in this study provided a fundamental database for the future application of GPA-ECC in civil infrastructure.