Impact Resistance of Functionally Layered Two-Stage Fibrous Concrete

Abstract

The impact resistance of functionally layered two-stage fibrous concrete (FLTSFC) prepared using the cement grout injection technique was examined in this study. The impact resistance of turtle shells served as the inspiration for the development of FLTSFC. Steel and polypropylene fibres are used in more significant quantities than usual in the outer layers of FLTSFC, resulting in significantly improved impact resistance. An experiment was carried out simultaneously to assess the efficacy of one-layered and two-layered concrete to assess the effectiveness of three-layered FLTSFC. When performing the drop-mass test ACI 544, a modified version of the impact test was suggested to reduce the scattered results. Instead of a solid cylindrical specimen with no notch, a line-notched specimen was used instead. This improvement allows for the pre-definition of a fracture route and the reduction of the scattering of results. The testing criteria used in the experiments were impact numbers associated to first crack and failure, mode of failure, and ductility index. The coefficient of variation of the ACI impact test was lowered due to the proposed change, indicating that the scattering of results was substantially reduced. This research contributes to the idea of developing enhanced, more impact-resistant fibre composites for use in possible protective structures in the future.

The Effect of Low-Modulus Plastic Fiber on the Physical and Technical Characteristics of Modified Heavy Concretes Based on Polycarboxylates and Microsilica

“…The use of this material can increase the tensile strength of the cement matrix, allowing a cement concrete of higher flexural strength to be obtained [ 21 ]. It is recommended to use polypropylene fiber in the technology of fiber concrete to reduce the delamination of mixtures, increase water resistance, frost resistance, corrosion resistance, and impact strength, and reduce abrasion [ 2 , 22 ]. In addition, polypropylene fiber is characterized by corrosion resistance in various environments [ 23 ].…”

Repeated Drop-Weight Impact Testing of Fibrous Concrete: State-Of-The-Art Literature Review, Analysis of Results Variation and Test Improvement Suggestions

“…The p -values of the obtained impact results (based on the Kolmogorov–Smirnov test) showed that these results hardly followed the normal distribution. Murali et al [ 49 ] conducted repeated impact tests on concrete specimens that included green substitutions to cement and fine aggregate, where two identical mixtures were prepared with or without 0.5% of 50 mm length hooked-end SF. The cement was partially replaced with 2% of nano silica, while 30% of the fine aggregate was replaced with copper slag.…”

“…However, comparing the results presented by the authors, it is clear that on average, for all mixtures, the case with line notch and sand bedding resulted in the best scattering reduction results, where the percentage reduction in the COV was in the range of 58 to 66% for the five mixtures, which supports the results of Abid et al [ 69 ]. Murali et al [ 49 ] tested the impact resistance of eleven functionally graded, preplaced concrete mixtures reinforced with hybrid steel–polypropylene fibers using the line notched specimens and line load-transferring plate. Fifteen specimens were tested from each mixture, and seriously low COV values of 5.9 to 16.6% were reported.…”

“…However, significant research was conducted during the last few years using the repeated impact test procedure. The ACI 544-2R repeated impact test was used to evaluate the impact performance of several types of cementitious mixtures in the literature, including normal-strength and high-strength concrete [ 29 ], steel-fiber-reinforced concrete [ 30 , 31 , 32 ], synthetic-fiber-reinforced concrete [ 33 , 34 , 35 , 36 , 37 ], hybrid-fiber-reinforced concrete [ 30 , 38 , 39 , 40 ], plain and fibrous self-compacting concrete [ 41 , 42 , 43 , 44 , 45 , 46 , 47 ], high-performance and ultra-high-performance concrete [ 48 , 49 , 50 , 51 , 52 ], engineered cementitious composites [ 53 , 54 , 55 , 56 ], plain and fibrous preplaced aggregate concrete [ 57 , 58 , 59 , 60 , 61 ] and layered concrete [ 62 , 63 ]. On the other hand, other studies tried to investigate the effect of the addition of some materials and additives, such as crumb rubber [ 41 , 44 , 64 ], recycled materials [ 42 , 43 , 65 ], natural fibers [ 6 , 36 ], nano material [ 66 ,…”

Effect of Steel Fiber on the Strength and Flexural Characteristics of Coconut Shell Concrete Partially Blended with Fly Ash

“…This method was used to create fiber reinforced concrete (FRC) in the 20th century, which gained popularity in the building sector because of its increased strength. Steel fiber incorporation in the cement matrix improves the toughness, yield load, first cracking load, moment of resistance, and crack resistance of reinforced concrete beams subjected to transverse loading, according to research on fiber-reinforced concrete [54][55][56][57][58][59][60]. The improvement in the ductility for fiber addition, on the other hand, is a critical characteristic for structural concrete members.…”