Multi-layered two stage fibrous composites against low-velocity falling mass and projectile impact

Abstract

The Multi-layer Two Stage Fibrous Composite (MTSFC) is an innovative type of composite that has gained popularity in recent years and pulled the attention of researchers on global level. The process of preparation composes the subsequent two key actions; first, the natural coarse aggregate skeleton is formed by piling the coarse aggregates and fibres in a particular way; second, the artificially formed skeleton is fully filled with cement grout by gravity method. In the present study, the effect of Glass Fibre Mesh (GFM) insertion on MTSFC is researched by subjecting to falling mass and projectile impacts. Totally, twenty one mixtures with insertion of GFM of varied diameters and with different layout in between the layers are designed and tested under falling mass and projectile impacts. Additionally, the hooked end fibre at a dosage of 2.5% volume of composite was constantly used for all designed mixtures. The purpose of inserting glass fibre mesh in between the top-middle and middle-bottom layer is to play a role of trapping layer in order to prevent/delay the crack propagation. The multiple number of hits to provoke crack initiation and crack ultimate, impact energy at crack initiation and crack ultimate, impact ductility index, front damage area, bottom damage area, damage ratio, depth of penetration and damage pattern are studied hereby. The findings revealed that the GFM reinforcement stratagem combined with steel fibres in MTSFC, turned out to deliver high resistance against impact load and extends the failure duration by absorbing more energy. Also, findings indicated that the depth of penetration, damage area and damage ratio were raised with the number of hits and were lessened by the high content steel fibres together with GFM and coarse aggregate. Consequently, the effect of GFM insertion is minimal when it is placed inbetween top-middle layer. Preferably, it is best to insert GFM inbetween mid-bottom layer in the MTSFC, which extends to delay the crack proliferation while tensile stress are being transformed and offers more impact energy absorbance. The research outcomes obtained from this study is to deliver a baseline information for continuing a deeper research work on MTSFC under impact.