Concrete is the most commonly used and essential material in the construction industry, and it is also the most widely utilized product globally. The construction industry is a rapidly expanding industry. To improve the efficiency and strength properties of concrete, researchers from all over the world continue to search for supplementary cementitious materials (SCMs) and industrial by-products that can be incorporated as alternative materials. The current study aimed to determine the effects of partially substituting coir pith ash (CPA) for cement in coconut shell concrete, in addition to utilizing steel and coconut fibers. Various percentages of CPA were used to replace cement in the concrete mixes, ranging from 5% to 20% by cement weight. Steel fibers were utilized in this study at volume ratios of 0.25%, 0.5%, 0.75%, and 1.0%, and coconut fibers were utilized at volume ratios of 0.1% to 0.5% with an increment of 0.1% in the concrete to achieve the desired results. Various properties have been examined, such as workability, mechanical, durability, and morphological tests. The addition of coir pith ash to concrete increased its compressive, flexural, and tensile strengths by 10.36%, 8.75%, and 7.7% at 28 days compared to control concrete. The incorporation of coconut fiber and coconut shell in concrete production improves its performance and strength while also preserving natural resources and offering a solution to the problem of disposing of solid waste.

A characteristic study on the phenol formaldehyde (PF) composite is carried out based on the micro level bio waste particles such as wood sawdust (WSD) and coir pith (CP). Composite is characterized by mechanical properties such as tensile, flexural and impact at different percentages of particles (0-50% by weight) to find out the optimum percentage of particle loading to get the maximum properties. The WSD/CP/PF hybrid composite is also prepared by two different methods i.e., one: one (1:1) ratio and rule of mixture. The first method (1:1) is used to find out the optimum level of hybrid particles loading to get the maximum properties. But, the second method is followed to find out the weight percentages of particles influencing the properties of resulting composite. The results show that the mechanical properties of WSD/PF are higher than CP/PF composite in the entire particle loading. The optimum particle loading to get the maximum properties is 40 wt.% in CP/PF composite, whereas for WSD/PF composite are at 30 wt.%. The hybrid composite (1:1) also gives the maximum properties at 30 wt.%. Moreover, the hybrid composite (20WSD/10CP) prepared by rule of mixture showed the highest mechanical properties compared to the other particle loading. It is identified that the WSD particles are most influencing the properties of PF composites than the CP particles. Fractographic study was performed using scanning electron microscope to examine the failure mechanism of the composite specimens.

In this study, Wood Dust (WD)/Phenol Formaldehyde (PF) and Coir Pith (CP)/PF composites were hybridized with the Prosopis Juliflora Fiber (PJF) to obtain the hybrid composites. Composites were prepared by hand moulding technique. The weight percentage of particles and fibers are fixed in the ratio of 1:1. Mechanical properties such as tensile, flexural and impact strengths were evaluated as a function of the particle and fiber loadings. The results show that the properties of both the WD and CP composites obviously improved by the addition of the PJF. The improvement in WD/PF composites was obviously higher than the CP/PF composites for all loadings. The WD/PJF/PF hybrid composites exhibited better tensile (strength of 48.9 MPA and modulus of 1262.1 MPa, respectively), flexural (strength of 55.4 MPa and modulus of 1344.3 MPa, respectively), and impact properties (1.32 KJ/m2).Â

Natural fiber-reinforced polymer composites have several advantages over traditional composites. The chemical modification of natural fibers helps to develop polymer composites with better mechanical properties. In the present work, mechanical properties such as tensile, flexural, and impact strength of chopped Screw pine fiber reinforced vinyl ester composites have been evaluated under-treated conditions based on the volume fractions of Screw pine fibers. The fibers have been treated with 5% of NaOH solution for 1 h at room temperature. The hand lay-up method has been used to prepare composite plates at room temperature. The results revealed that mechanical properties of composites increased with the increase of the fiber content up to 35.57 vol% at both the untreated and treated conditions and then dropped. However, the modulus values have been increased continuously from the fiber content of 8.43 to 45.3 vol%. It was identified that the critical or optimum fiber content for better mechanical properties is 35.57 vol% for both the untreated and treated conditions. The percentage of improvement at every combination was obtained by comparing the composites prepared with the untreated and treated fibers. The fractured surface of the treated fiber composites was examined by scanning electron microscopy. Moreover, the tensile properties are predicted using the Hirsch and Modified Bowyer and Bader model and compared with experimental values. The predicted results revealed that the Modified Bowyer and Bader model shows better conformity.

Mechanical properties of Roselle fiber reinforced vinyl ester biocomposite were studied based on the fiber content and length in the present communication. Usually, natural fiber reinforced polymer composites depend on some aspects such as fiber content, fiber length and orientation, the fiber-matrix adhesion. Composite plates were prepared by a simple hand lay-up technique for two different fiber lengths (3 and 13 mm) and five different fiber content (10, 20, 30, 40 and 50 wt%). Composite specimens were tested according to ASTM standards and their results were recorded. Experimental results showed that mechanical properties such as tensile, flexural and impact, increases with increase of fiber content up to 40 wt% after which it is decreases at both the fiber length. However, modulus values were increased linearly with fiber content of 10 to 50 wt%. Composites with the fiber length of 13 mm show the high level of mechanical properties compared to composites with the fiber length of 3 mm at all combinations of fiber contents. It is observed that the optimal fiber content is 40 wt%, which can be used to obtain the maximum property level in the Roselle fiber reinforced vinyl ester composites