Coconut shell concrete is one of the recently established lightweight concretes. This paper discusses the optimization of adding coconut fibers in both coconut shell concrete and conventional concrete. Coconut fibers at different aspect ratios of 16.67, 33.33, 50, 66.67, 83.33, and 100 and volume fractions of 1, 2, 3, 4, and 5% were tried. The maximum compressive strength was attained at an aspect ratio of 83.33 and volume fraction of 3% for conventional concrete, and aspect ratio 66.67 and volume fraction 3% for coconut shell concrete. Flexural strength increased by 30.63% (conventional concrete) and 53.66% (coconut shell concrete) on the addition of coconut fibers. Similarly, the split tensile strength increased by 19.44% and 30%, respectively. The number of blows needed for failure of specimen in impact resistance test was more for concrete mixed with fibers. The experimental bond stresses were higher than the theoretical values recommended by IS 456: 2000 (Indian Standard) and BS 8110 (British Standard). This study shows that the addition of coconut fiber enhances the properties of both conventional and coconut shell concrete.

Coconut fiber was used in coconut shell concrete (CSC) and its durability properties were studied. The properties include: water absorption, volume of permeable pore voids, rapid chloride penetration test, sorptivity and resistance at elevated temperature. For comparison purpose, these properties were also studied on conventional concrete (CC) with coconut fibers. Three different curing conditions viz. full water immersion, site curing and air-dry conditions were employed except for temperature resistance study in which only full water immersion was used. Test results show that the durability properties were better in full water immersion condition in case of CC mixes and in site curing condition in case of CSC mixes. Temperature resistance tests gave a minimum guarantee of both CC and CSC mixes without and with coconut fibers for 2 h resistance and hence they were deemed safe for construction.

In this study, we investigated using coconut shell concrete (CSC) in double-skin steel plate sandwich beams, i.e., steel–concrete–steel (SCS) under flexure. Two cases—without and with shear studs to interconnect the bottom tension and top compression plates—were considered. Conventional concrete (CC) was used for comparison purposes. The effect of quarry dust (QD) in place of river sand (RS) was considered. Therefore, four mixes named as CC, conventional concrete produced using QD (CCQ), CSC and coconut shell concrete produced using QD (CSCQ) were used. Three different steel plate thicknesses were considered (4 mm, 6 mm and 8 mm). In total, twelve SCS specimens were tested to evaluate the flexural performance under two-point static loads. Study parameters include: partial and fully composite, ultimate moment and failures, deflection characteristics, ductility property, cracking behavior and strains in both tension and compression plates. It was found that the moment carrying capacity of the SCS sandwich beams increased when the thickness of the steel plate increased. Our results provided evidence that using QD in place of RS augmented the strength of beams. Theoretical deflections were underestimated the experimental deflection, except in one case. The SCS beams showed good ductility behavior. The SCS beams exhibited crack widths at yielding well below guideline values.

The main objective of this study is to use coconut husk to produce mortar for ferrocement. Mortar mix proportions are selected per ACI codes’ recommendation and the WRD Handbook. Four types of mortars: Cement and River Sand mortar (CSM), Cement, River Sand and Steel fibre mortar (CSSFM), Cement and Coconut Husk mortar (CCHM), and Cement, River Sand (60%), Coconut Husk (40%), and Steel fibre mortar (CSCHSFM) are used for this study Microstructural studies like SEM, EDX, XRD, and FTIR analysis on cement mortar constituents and mortar mixes are studied and reported. At 3, 7, and 28 days tests of hardened mortar, such as compressive, split tensile, flexural strength, and impact strength resistance, were studied. Test results revealed that the coconut husk is innovative and sustainable and could be an alternative fine aggregate that can be utilized in place of river sand, which in turn can be used for mortar production. Since it has a lesser density which proves to be an advantage for developing lightweight mortar, it can be used for ferrocement applications.

Many researches on double skin sandwich having top and bottom steel plates and in between concrete core called as steel-concrete-steel (SCS) were carried out by them on this SCS type using with different materials. Yet, use of coconut shell concrete (CSC) as a core material on this SCS form construction and their results are very limited. Study investigated to use j-hook shear studs under flexure in the concept of steel-concrete-steel (SCS) in which the core concrete was CSC. To compare the results of CSC, the conventional concrete (CC) was also considered. To study the effect of quarry dust (QD) in its place of river sand (RS) was also taken. Hence four different mixes two without QD and two with QD both in CC and CSC was considered. The problem statement is to examine about partial and fully composite, moment capacity, deflection and ductility properties of CSC used SCS form of construction. Core concrete strength and the j-hook shear studs used are influences the moment carrying capacity of the SCS beams. Use of QD in its place of RS enhances the strength of concrete produced. Deflections predicted theoretically were compared with experimental results. The SCS beams showed good ductility behavior.