Chapter 2 REVIEW OF RELATED LITERATURE AND RELATED STUDIES This chapter presents the literature, studies conducted, and the readings significantly related to this present study. Hence, they serve and provide essential background to this study. The scientific name for coconut is Cocos nucifera. Early Spanish explorers called it coco, which means “monkey face” because the three indentations (eyes) on the hairy nut resembles the head and face of a monkey. Nucifera means “nut-bearing.” The coconut provides a nutritious source of meat, juice, milk, and oil that has fed and nourished populations around the world for generations. On many islands, coconut is a staple in the diet and provides the majority of the food eaten. Nearly one third of the world’s population depends on coconut to some degree for their food and their economy. Among these cultures, the coconut has a long and respected history. Coconut is said to be the tree of life. You can get any product from its roots up to its leaves. In the context of the Philippines, coconut is very important. Almost 25 percent of cultivated land is planted with it. Most Filipinos, approximately 33 percent are depending on it mainly because it supports their family and their livelihood in general. Copra is the most produced product from coconuts by the Filipinos though there are some products they also produce like copra cake, coconut oil, desiccated coconut, coconut vinegar, coconut husks, handicrafts, and many more. These products generate the largest agri-food export but over the years, the industry does not perform well due to some reasons.
Why is the industry that important? First, coconut farms are reportedly present in 68 out of 79 provinces. Second, coconut farms cover some 3.3 million hectares (ha), nearly 30% of farmlands. Third, coconut regions host among the largest number of rural poor. Fourth, coconut products contribute nearly half of agriculture exports. Fifth, coconut lands have among the largest potential for diversification among the major crops. Last but not the least, it has a huge, untapped resource pool for industry development. Table 2.1 Availability of Coconut
Coconut shell is the strongest part covered in coconut fruit. Coconut shell is located in between the coconut flesh and coconut husk. This shell is naturally created to protect the inner part of coconut. The shell is used to produce various handicraft and other applications. Most of handmade decorative are created by using coconut shell due to their strength. Coconut shells are also used to made charcoal which is used as fuel and coconut charcoals are far better than other charcoals. Coconut shell has high strength and modulus properties. It has added advantage of high lignin content. High lignin content makes the composites more weather resistant.
It has low cellulose content due to which it absorb less moisture as compared to other agriculture waste. Coconut, being naturally available in nature and since its shells are non-biodegradable, they can be used readily in concrete which may fulfil almost all the qualities of the original form of concrete. The coconut shell is still underutilized in some places. The chemical composition of the coconut shell is similar to wood. It contains 33.61% cellulose, 36.51% lignin, 29.27% and ash at 0.61%. Lightweight concrete is typically made by incorporating natural or synthetic lightweight aggregates or by entraining air into a concrete mixture. Coconut shell exhibits more resistance against crushing, impact and abrasion, compared to crushed granite aggregate. Coconut shell can be grouped under lightweight aggregate. There is no need to treat the coconut shell before use as an aggregate except for water absorption. Coconut shell is compatible with the cement. Olanipekun (2006) carried out the comparative cost analysis and strength characteristics of concrete produced using crushed, granular coconut and palm kernel shell as substitutes for conventional coarse aggregate. The main objective is to encourage the use of waste products as construction materials in low-cost housing. Crushed granular coconut and palm kernel was used as substitute for conventional coarse aggregate in the following ratios: 0%, 25%, 50%, 75% and 100% for preparing of mix ratios 1:1:2 and 1:2:4. Total 320 cubes were casted, tested and their physical and mechanical properties were determined. The result showed that the compressive strength of the concrete decrease as the percentage of the coconut shell increases in the two mix ratios, Coconut shell exhibited a higher compressive strength than palm kernel shell in the test. Moreover,
there is a cost reduction of 30% and 42% for concrete produced from coconut shell and palm kernel shell respectively. Ahlawat and Kalurkar (2014) explored the possibility of producing M20 grade of concrete by replacing conventional aggregate of granite by coconut shell. Forty five cubes were casted. Percentage of replacement of conventional coarse aggregate by coconut shell were 2.5%, 5%, 7.5%, 10%. Compressive strength were 19.71, 19.53, 19.08, 18.91 N/mm2 respectively at 28 days. Workability and compressive strength had been evaluated at 7, 14 and 28 days. The compressive strength of concrete reduced as the percentage replacement increased. By these results it can be concluded that coconut shell concrete can be used in reinforced concrete construction. Author concluded that its utilization is cost effective and eco-friendly.
