Nanomodified Cementitious Composites Incorporating Basalt Fiber Pellets under Tensile and Impact Loads

摘要

This study investigated the behavior of nanomodified cementitious composites reinforced with innovative basalt fiber pellets (BFP), with specially tailored surface texture under quasi-static (direct) tensile as well as static and dynamic compression (split Hopkinson pressure bar) loading schemes. The composites comprised two different binder formulations (50% fly ash or slag replacement) with/without nanosilica modification. Thermogravimetric and microscopy studies were conducted to evaluate the hydration development and microstructure of the binders. Moreover, the pellet/matrix interfacial bond properties were assessed using the single pellet pullout test. The results showed the efficacy of BFP in reinforcing the cementitious composites and highlighted the role of nanosilica at enhancing the postcracking performance of high-volume fly ash- and slag-based mixtures under all loading schemes. Furthermore, the increase of the pellets' dosage improved the ductility of composites in terms of energy absorption capacity and strain at failure. The pellet/matrix interface, which is responsible for the main toughening mechanism of the composites by pullout, was sensitive to the type of binder and imposed displacement rate.