Mechanical properties of high ductile alkali-activated fiber reinforced composites with different curing ages

Combining the high ductility of engineered cementitious composites and sustainable advantages of alkali activated materials, high ductile alkali-activated fiber reinforced composite (AAFRC) is receiving a lot of attentions. In this paper, ground granulated blast-furnace slag (or slag)-based, polyethylene fiber reinforced AAFRCs were prepared. The macro- and meso-scale mechanical properties of the mixes with different curing ages varying from 1d to 120d were experimental investigated. The results show that both the compressive strength and the tensile strength increase first and then stabilize with the ages increasing, nonetheless reaching the maximum values of 100.7 MPa at 28d and 5.99 MPa at 56d, respectively. The tensile strain capacities maintain a higher level of 5.74-6.14% after 7d. At meso-scale, the parameters derived from three-point bending, single crack tensile and single fiber pullout tests can be well correlated with the tensile properties of the studied mixes at different ages. The analysis of FT-IR reveals that the amorphous silicate and aluminosilicate gels are the main polymerization reaction products; and the crosslinking degree of the gels has a tendency to be higher after 7d.