The effects of steel fiber alignment and high-volume mineral admixture replacement [Class C fly ash (FA) and ground granulated blast furnace slag (GGBS)] on the mechanical properties of SIFCON (Slurry Infiltrated Fiber Concrete) have been investigated. Ordinary portland cement was replaced with 50% (by weight) FA or GGBS in SIFCON slurries, and two different steel fiber alignments (random and oriented in one direction) were used. Test results showed that FA and GGBS replacement positively affected mechanical properties (compressive and flexural strength and fracture energy) and fiber alignment is an important factor for superior performance. Binary combination of improved matrices (low water/binder ratio and mineral admixture replacement) and proper fiber orientation enhances mechanical performance, particularly flexural properties of SIFCON. Flexural strength and fracture energy of this composite are 138 MPa and 195,815 N/m, respectively. Scanning electron microscope investigations revealed tobermorite-l...

Fiber-matrix bond properties of alkali-activated slag cements (AASC)–based composites have not been studied comprehensively in literature. Within the scope of this study, the effects of AASC matrix phase composition and the silicate modulus of activator solution on the pullout behavior of steel fiber were investigated under water- and steam-curing conditions. Test results showed that AASC have a superior bond strength compared to portland cement (PC). Bond strength of AASC mortars with a compressive strength greater than 18 MPa were found higher than that of PC mortar with a compressive strength of 55 MPa. When the compressive strength of AASCs is higher than 40 MPa, the bond strength of AASC exceeds the bond strength of PC mortars that have compressive strength of 120 MPa. Microstructural analysis revealed that the map cracking in the fiber-matrix transition zone, which was induced by high drying shrinkage of AASC, can be eliminated by incorporating pozzolans. Consequently, it is possible to prod...