Response of Novel Functionally-Graded Prepacked Aggregate Fibrous Concrete against Low Velocity Repeated Projectile Impacts

Abstract

Preplaced Aggregate Fibrous Concrete (PAFC) is a newly minted composite that has recently become more popular. The production of PAFC involves two essential processes; first, the fibres and coarse aggregate were filled into the empty framework to form the first layer of a natural skeleton, followed by grout injecting. A cement grout fills the voids in the first layer skeleton with slight compaction. This process is repeated to complete the remaining layers; hence, a type of Functionally-graded Preplaced Aggregate Fibrous Concrete (FPAFC) is obtained. The most recent studies revealed that the literature regarding the high-velocity projectile impact on fibrous concrete is well documented; however, the low-velocity repeated projectile impact on PAFC is still unexplored and needs particular emphasis. This research aims to investigate the FPAFC made with a new type of steel and polypropylene fibres against low-velocity projectile impact to fill this research gap. In the current study, twelve mixes were prepared with mono and hybrid combinations of fibres for pioneering the possible utilization of fibres in FPAFC. The maximum fibre dosage in this study is limited to 2.4%. The projectile impact resistance of FPAFC was assessed in line with penetration depth, front and rear damage surface area, weight loss, damage ratio and failure pattern. Additionally, a simplified analytical model was introduced to compute the ejected composite mass from the tested specimens. The results revealed that the addition of steel fibre in a single layer FPAFC exhibited an increasing compressive strength trend compared to the two/three-layered FPAFC. Furthermore, increasing the dosage of fibre at the bottom and top layers of FPAFC with a hybrid combination alleviates the spalling with an increasing number of impacts. The results from this research offer the reference information for more detailed research and studies of FPAFC under low-velocity projectile impact.

Impact Response of Preplaced Aggregate Fibrous Concrete Hammerhead Pier Beam Designed with Topology Optimization

“…The addition of fiber increased the impact energy absorption and delayed the crack initiation [46]. The steel fibers significantly contributed to arresting crack propagation in the meantime, transmitting the energy effectively [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66]. Fully fibered concrete HPB-2 and HPB-4 were 2318.4 J and 2725.1 J, respectively, had impact energy at the initial crack while compared with the Tension zone fibered concrete HPB-2-T and HPB-4-T were 325.4 J and 488.1 J, respectively.…”

Methods of systemic management of the service life of vehicles

“…The increasing complexity of the vehicle design contributes to an increase in costs, both for spare parts and for maintenance and repair complexes, as well as for operating materials. However, these changes are also made possible to consider when building a multi-criteria model based on the data given, for example, in [19][20][21][22] on the specifics of innovative building and machine-building materials.…”

Impact Resistance of Functionally Layered Two-Stage Fibrous Concrete

“…Compared to PAC, the compressive strength was improved by 23% and 26% for the specimens D-PF-SF and D-SF-PF, respectively. However, evenly distributed SF and PF at the top or bottom layers could avoid macro fractures, increasing compressive strength [44]. The load distribution on the concrete's outer layers modified the fracture route and decreased the development of crack by the action of fibre bridging [45].…”