A feasibility of enhancing the impact resistance of hybrid fibrous geopolymer composites: Experiments and modelling

The latest research data indicates that geopolymer concrete reinforced with mono fibre has a remarkable enhancement in its impact strength and fracture toughness, which is well documented. Nevertheless, many aspects of impact behaviour of Hybrid Fibrous Geopolymer Composites (HFGC) are still unexplored, which are of primary importance for defense projects in the world. For the first time, the impact behaviour under falling weight collision of HFGC were evaluated and further analysed. The HFGC mixtures were fabricated using three different fibres viz., 5D hooked end steel, polypropylene and glass. The main parameters studied were the fibre dosage and amalgamations of different fibres. Totally seven mixes were prepared and further investigations were conducted in two phases. In the first phase, five cylindrical specimens were fabricated for each mix and tested as per the ACI committee 544 falling weight collision test recommendations. Subsequently, a comprehensive two-parameter Weibull distribution was executed to scrutinise the scattered experimental test results of cylindrical specimens and presented in terms of reliability function. In the second phase, prism specimens were fabricated and tested under the same falling weight collision. Then, an analytical model was formulated for evaluating the impact energy at failure of HFGC prism specimens and comparisons were made with experimental data. The hybridisation of the above three fibres at a certain dosage and incorporation in geopolymer composites led to an enhanced impact performance and ductility properties. Further, the obtained impact energy at failure from modelling well agrees with the experimental results. Henceforth, it is a successful research data that is presented herein which will be eminently valuable for understanding the performance of new fibrous geopolymer composites (FGC) made with hybrid fibres that which are available all over the world. (C) 2019 Elsevier Ltd. All rights reserved.