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The primary objective of this study is to produce one-way slabs made of LWFC with low density and sufficient compressive strength suitable for structural purpose then investigate their flexural behavior under various types of reinforcement and thickness of the slab and the influence of addition of PP fibers reinforcement on the mechanical behavior of reinforced concrete slabs. The specimens were tested using four-point loading. The results concerning load capacity, deflection and failure mode and crack pattern for each specimen were obtained. Also, an analytical investigation of PP fiber and GFG contribution on the flexural behavior of foamed concrete slabs is studied to investigate the significant role of PP fiber on the stress distribution in reinforced foam concrete and predict the flexural moment capacity.

The materials used in this study are cement, fine aggregate (sand), water, PP fibers, foaming agent, chemical additives if required, steel reinforcing rebars and glass fiber grid. The combination of these constituent materials will be used to produce foamed concrete in this research Then this study will present the experimental program of one-way foamed concrete slabs including slabs reinforced with GFR grids and another with steel reinforcements. The slabs will be tested in the laboratory under static loading conditions to investigate their ultimate capacities. The flexural behavior is to the interest of the slabs reinforced with GFR grids reinforcements in comparison with that of one with steel reinforcing rebars. Three groups are considered. (1) Group I: two slabs of PP fiber foamed concrete with minimum required reinforcements. (2) Group II: two slabs of PP fiber foamed concrete with glass fiber grids. (3) Group III: two slabs of PP fiber foamed concrete with the minimum required reinforcements and glass fiber grids.

The experimental results proved the effectiveness and efficiency of this the new system in producing a low density of concrete below 1900 kg/m³ had a corresponding strength of about 17 MPa at least. Besides, the presence of PP fibers had a noticeable improvement on the flexural strength values for all the examined slabs. It was found that the specimens reinforced with steel reinforcement mesh carried higher flexural capacity compared to these reinforced with GFG only. The specimens reinforced with GFG exhibited the lowest flexural capacity due to GFG separation from the concrete substrate. Also, an analytical investigation to predict the flexural strength of all tested specimens was carried out. The analytical results were agreed with the experimental results. Therefore, LWFC can be used as a substitute lightweight concrete material for the production of structural concrete applications in the construction industries today.

Foamed concrete is a wide field to discuss. To achieve the objectives of the project, the study is focused on the foamed concrete with the following limitations: (1) because the aim of this research is to produce foamed concrete suitable for structural purposes, it is decided to produce mixes within the density range 1300–1900 kg/m³. (2) Simply-supported slabs are of considered. (3) This study also looks out by using GFR and without it.

The main objectives of this study were producing structural foamed concrete slabs and investigate their flexural response for residential uses.

Many additively manufactured parts suffer from reduced interlayer strength. This anisotropy is necessarily tied to the orientation during manufacture. When individual features on a part have conflicting optimal orientations, the part is unavoidably compromised. This paper aims to demonstrate a strategy in which conflicting features can be functionally separated into “co-parts” which are individually aligned in an optimal orientation, selectively reinforced with continuous fiber, printed simultaneously and, finally, assembled into a composite part with substantially improved performance.

Several candidate parts were selected for co-part decomposition. They were printed as standard fused filament fabrication plastic parts, parts reinforced with continuous fiber in one plane and co-part assemblies both with and without continuous fiber reinforcement (CFR). All parts were loaded until failure. Additionally, parts representative of common suboptimally oriented features (“unit tests”) were similarly printed and tested.

CFR delivered substantial improvement over unreinforced plastic-only parts in both standard parts and co-part assemblies, as expected. Reinforced parts held up to 2.5x the ultimate load of equivalent plastic-only parts. The co-part strategy delivered even greater improvement, particularly when also reinforced with continuous fiber. Plastic-only co-part assemblies held up to 3.2x the ultimate load of equivalent plastic only parts. Continuous fiber reinforced co-part assemblies held up to 6.4x the ultimate load of equivalent plastic-only parts. Additionally, the thought process behind general co-part design is explored and a vision of simulation-driven automated co-part implementation is discussed.

This technique is a novel way to overcome one of the most common challenges preventing the functional use of additively manufactured parts. It delivers compelling performance with continuous carbon fiber reinforcement in 3D printed parts. Further study could extend the technique to any anisotropic manufacturing method, additive or otherwise.

This study aims to investigate the optimum proportion of coconut fibre and cement suitable for rammed earth wall construction. Coconut fibres and cement can be easily incorporated into the soil mixture which adds strength and durability to the wall. This paper highlights the salient observations from a systematic investigation on the effect of coconut fibre on the performance of stabilized rammed earth blocks.

Stabilization of soil was done by adding Ordinary Portland Cement (2.5, 5.0, 7.5 and 10.0 per cent by weight of soil), whereas coconut fibre in length about 15 mm was added (0.2, 0.4, 0.6, 0.8 and 1.0 per cent by weight of soil) as reinforcement. Thirty types of mixes were created by adding different proportions of cement and fibre to locally available soil and compacting the mix at constant compaction energy in three layers with Proctor rammer.

Samples were tested for compressive strength and tensile strength, and failure patterns were analysed. The use of cement and fibre increases ultimate strengths significantly up to an optimum limit of 0.8 per cent fibre content, provides a secondary benefit of keeping material bound together after failure and increases residual strength. Benefits of fibre reinforcement includes both improved ductility in comparison with raw blocks and inhibition of crack propagation after its initial formation.

After analysing the results, it is recommended to use 0.8 per cent fibre and 5-10 per cent cement by weight of soil to achieve considerable strength. This research may add a value in the areas of green and sustainable housing, waste utilization, etc.

The tribological behavior of composites varies on matrices materials, the reinforcement material and the direction of reinforcement materials. The purpose of this study is to examine the effects of fiber orientation on the tribological properties of carbon fiber–reinforced epoxy composite.

The experiments were carried out with a pin-on-ring tribometer. The tests were executed according to three different parameters: load, sliding velocity and direction of reinforcement. Loads measuring 92 N and 150 N were applied at sliding velocities of 1 and 2 m/s, in parallel, antiparallel and normal directions of fiber reinforcements. The frictional force was read every 500 m of sliding distance. To calculate specific wear rate, the mass of the samples was measured before and after each experiment. Moreover, temperature was measured every 1000 m of sliding distance via three-point infrared thermometer, to examine the effect of temperature variations. The sample surfaces were also examined in optic microscope after the experiments. Higher friction coefficient values were obtained in the normal direction-oriented carbon fiber specimen.

Comparing the friction coefficient values, antiparallel and parallel direction-oriented carbon fiber specimens gave lower friction coefficient values. The increase of sliding velocity and normal load resulted in the increase of surface temperature and this lead to the increase of friction coefficient.

This study shows the effects of fiber orientation on the tribological behavior of carbon fiber–reinforced epoxy composite. According to fiber orientations, relatively moving counter surfaces of this material shows different tribological behaviors.

Continuous fiber reinforced thermoplastic composites (CFRTPCs) with great mechanical properties and green recyclability have been widely used in aerospace, transportation, sports and leisure products, etc. However, the conventional molding technologies of CFRTPCs, with high cost and low efficiency, limit the property design and broad application of composite materials. The purpose of this paper is to study the effect of the 3D printing process on the integrated rapid manufacturing of CFRTPCs.

Tensile and flexural simulations and tests were performed on CFRTPCs. The effect of key process parameters on mechanical properties and molding qualities was evaluated individually and mutually to optimize the printing process. The micro morphologies of tensile and flexural breakages of the printed CFRTPCs were observed and analyzed to study the failure mechanism.

The results proved that the suitable process parameters for great printing qualities and mechanical properties included the glass hot bed with the microporous and solid glue coatings at 60°C and the nozzle temperature at 295°C. The best parameters of the nozzle temperature, layer thickness, feed rate and printing speed for the best elastic modulus and tensile strength were 285°C, 0.5 mm, 6.5r/min and 500 mm/min, respectively, whereas those for the smallest sectional porosity were 305°C, 0.6 mm, 5.5r/min and 550 mm/min, respectively.

This work promises a significant contribution to the improvement of the printing quality and mechanical properties of 3D printed CFRTPCs parts by the optimization of 3D printing processes.

The fiber reinforced polymer composites are becoming more critical because of their exceptional mechanical properties and lightweight structures. Fused filament fabrication (FFF) is a three-dimensional (3D) printing technique that can manufacture composite structures. However, the effect of impact performance on the structural integrity of FFF made composites compared to the pre-preg composites is a primary concern for the practical usage of 3D printed parts. Therefore, this paper aims to investigate the effect of different processing parameters on the impact performance of 3D printed composites.

This paper investigates the impact of build orientation, fiber stacking sequence and fiber angle on the impact properties. Two build orientations, three fiber stacking sequences and two different fiber angles have been selected for this study. Charpy impact testing is carried out to investigate the impact energy absorption of the parts. Onyx as a matrix material and two different types of fibers, that is, fiberglass and high strength high temperature (HSHT) fiberglass as reinforcements, are used for the fabrication.

Results indicate that build orientation and fiber angle largely affect the impact performance of composite parts. The composite part built with XYZ orientation, 0º/90º fiber angle and B type fiber stacking sequence resulted into maximum impact energy. However, comparing both types of fiber reinforcement, HSHT fiberglass resulted in higher impact energy than regular fiberglass.

This study evaluates the damage modes during the impact testing of the 3D printed composite parts. The impact energy absorbed by the composite samples during the impact testing is measured to compare the effect of different processing conditions. The investigation of different types of fiberglass reinforced with Onyx material is very limited for the FFF-based process. The results also provide a database to select the different parameters to obtain the required impact properties.

Recycled fibres used as reinforcements are obtained from garment cut wastes of cotton, polyester and cotton/polyester fabrics to develop these composites. These composites are developed by using Epoxy resin, Kaolinite, Polypropylene sheet as matrices. Reinforcements and matrices have been used in different compositions and combinations to develop these composites. The main advantages of this type of composites are to combine the different properties of different materials to obtain unique and high-performance material.

Garment cut wastes from apparel industries are used for various applications in various industries. Normally, garment cut wastes and recycled fibres from garment cut wastes are used in textile, furniture, carpet, paper, automobile, construction and agricultural industries in low mechanical performance applications. In this research, composites are developed by using recycled fibres obtained from garment cut wastes as reinforcement and with different types of matrices.

Technical properties like thickness, mass per unit area, Tensile strength, Flexural strength, Impact strength, Water absorbency and Scanning Electron Microscope of developed composites were tested and analyzed. The outcome of the results demonstrates that many of the composite proportions with different blend, reinforcement and matrcies show superior mechanical performances when compared with each other, and it can be recommended for many potential applications.

The properties of composites are dependent on the different blend proportions of recycled fibres with reinforcement and matrices. Based on the result of tensile strength, polyester/cotton fibre reinforced composites show superior strength compared to other recycled fibre reinforced samples and it can be suitably tailored further by appropriate design of different lay-up angle and orientation with the number of different preformed layers of reinforcements to suit the intended applications.

This research seeks to investigate the potential of using para‐aramid fibre fabric and yarn as an external reinforcement to existing structures. The purpose of this paper is to improve existing structural performance or to return the original design performance, during refurbishment. The research aims to investigate the potential for enhanced flexural strength and toughness in concrete beams, which may be required for change of use of buildings, where loadings may be subject to change. Buildings in earthquake zones may also benefit from additional toughness provided with external fabric/yarn reinforcement as a means of providing additional time for escape, for the occupants.

The test compared four types of concrete beams with different reinforcement material compositions and each set consisted of three beams. The beams were: plain reinforced concrete without any external form of reinforcement (RC), plain unreinforced beams with a para aramid sheet (KF), plain unreinforced beams with para aramid strips of yarn attached longitudinally (KY) and plain reinforced concrete beams with sheet fabric (RCKF). All of the para‐aramid material (fabric and yarn) was externally bonded to the samples, using a two part epoxy resin adhesive applied to a prepared surface. To determine the flexural strength and toughness a three point loading test was used to provide load and deflection data on the 12 (500 mm×100 mm×100 mm) concrete beams.

An increase in flexural strength and toughness was observed when para‐aramid was used in conjunction with steel reinforcement bar (re‐bar). The para‐aramid fabric and yarn produced similar results to the plain reinforced concrete beam in terms of flexural strength but not toughness.

An advantage of using para‐aramid as an external reinforcement, would be to utilise the large deflection the beam sustains under loading, whilst the fabric/yarn holds the beam together across the rupture plane. Although the testing did not prove that para‐aramid would be a viable alternative to steel re‐bar it did show that the material has the potential as an additional reinforcement that may be particularly useful where concrete structures are subject to large deformations or in need of repair.

This study aims at extracting and characterizing palm leaf fibers from Elaeis guineensis species of palm trees found in Ethiopia.

The fibers were extracted using three methods: manually, through water retting and chemically with sodium hydroxide. Physical parameters of the extracted fibers were evaluated, including tensile strength, fiber fineness, moisture content, degradation point and functional groups. Its cellulose, hemicellulose and lignin contents were also analyzed.

The results showed that the palm leaf fibers have a comparable fiber strength (170-450 MPa), elongation (0.95-1.25 per cent), fiber length (230-500 mm) and moisture regain (8-10 per cent) to jute, sisal and flax and thus can be used for technical textile application.

The fibers extracted using the water retting method had better properties than the other extraction methods. Its fiber length of 307 mm, cellulose content of 58 per cent, strength of 439 MPa and elongation of 1.24 per cent were the highest for all the extracted fibers. When compared with other fibers, palm leaf fiber properties such as tensile strength (439 MPa), elongation (1.24 per cent), moisture content (7.9-10.4 per cent and degradation point (360-380°C) were consistent with those of jute, sisal and ramie fibers. Hence, palm leaf fibers can be used for technical textile applications such as composite reinforcement.

This paper aims to investigate the resultant optimal ultimate tensile strength, elongation, flexural strength and modulus, compression strength and impact strength of fabricated alkali-treated Lagenaria siceraria fiber (LSF)-reinforced polymer matrix composite by optimizing input factors and microstructural characterization by influencing fiber length, fiber concentration and treatment condition of LSF.

The fabrication of LSF-reinforced composite specimens involved surface treatment followed by custom experimental design using a simple hand layup process. The wear analysis was performed by a multi-tribotester TR25 machine, and the developed model was validated by using statistical software Design Expert V.8 and analysis of variance (ANOVA). The surface morphology of the sample was also analyzed by field emission scanning electron microscopy.

The alkali treatment for LSFs had reduced the hemicellulose, and enhanced mechanical performance was observed for 30 wt.% concentration of L. siceraria in epoxy resin. Thermogravimetric analysis revealed thermal stability up to 245°C; microstructure revealed fiber entanglements in case of longer fiber length and compression strength reduction; and the surface-treated fiber composites exhibited reduced occurrences of defects and enhanced matrix–fiber bonding. Enhanced mechanical performances were observed, namely, ultimate tensile strength of 17.072 MPa, elongation of 1.847%, flexural strength of 50.4 MPa, flexural modulus of 3,376.31 GPa, compression strength of 52.154 MPa and impact strength of 0.53 joules.

The novel approach of optimizing and characterizing alkali surface-treated LSF-reinforced epoxy matrix composite was explored, varying fiber length and concentrations for specimens by empirical relations and experimental design to obtain optimal performance validated by ANOVA. Enhanced properties were obtained for: 7 mm fiber length and 30 wt.% concentration of fiber in the composite for alkali-treated fiber.