COCONUT WASTE AS A SUSTAINABLE MATERIAL FOR CONSTRUCTION IN MANABI

Abstract The relevance of sustainable materials in the construction sector is undeniable, facing both environmental and economic challenges in an industry known for its substantial pollution footprint. Using these materials not only can help to mitigate ecological impact but also to enhance the efficiency and quality of construction resources, leading to better performance of built structures and promoting a more balanced and sustainable approach in construction practices. A key characteristic of sustainable materials is their reusability. Discarded materials are transformed into new resources, allowing waste with various physical and mechanical properties to be incorporated as additives in composite material matrices. This thesis investigates the potential of coconut as a sustainable material, with fieldwork conducted in Manabí, Ecuador's second-largest coconut-producing province. Despite environmental regulations, there is a lack of a coconut waste management system for proper classification and subsequent reuse. Effectively treating these wastes aligns not only with sustainability and environmental responsibility but also with the ideals of the Fourth Industrial Revolution, where technology, innovation, and sustainability converge to transform both industry and society. Using coconut waste as an emerging composite material offers a valuable solution in urban areas where such waste poses an environmental challenge. Previous studies have shown promising results in using these wastes to generate new products, such as gardening elements, crafts, and briquettes. Coconut fiber has showed excellent hydrothermal properties for green roofs, thermal insulation, and activated charcoal production, among other uses. This research aims to develop a holistic approach for integrating coconut waste into the production of new sustainable materials. It investigates the coconut's lifecycle in specific communities of Portoviejo, Rocafuerte, and Manta cantons, near the Pacific Coastline in Ecuador. A detailed characterization of coconut fiber and endocarp properties is conducted, covering chemical, physical, mechanical, morphological, and thermal aspects. Two applications of coconut fiber in composite material matrices, such as mortars and polymers, are proposed. Mechanical tests will be performed to evaluate their compressive and flexural strengths. Both qualitative and quantitative approaches were used in this study. The research process began with a bibliographic analysis to contextualize the state-of-the art. Next, the empirical study started by collecting data about the coconut's lifecycle through interviews with various stakeholders: farmers, traders, consumers, and recyclers. Findings justified the need for a deeper scientific examination of coconut waste and its potential reuse. In the second stage, attention was focused on the characterization of coconut waste, using tests like X-ray Fluorescence (XRF), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). The results provided crucial information for an experimental study to identify how coconut fiber affects the matrices of mortars and polymers. The first phase of research revealed that coconut waste is mainly incinerated by farmers, with a minimal percentage used as fertilizer. Traders typically hand over this waste to solid waste collection services, while direct consumers dispose it in public containers. Among recyclers, a minority use the waste for crafts, caulking cords, coconut substrate, and one company notably uses imported coconut fiber from India for making slope stabilizing mats, as it is financially more convenient than collecting and processing it in Manabí. The physical, mechanical, chemical, morphological, and thermal test results showed that the coconut fiber has a tubular morphology with concentric microfibrils, specific weight of 0.69 g/cm3, tensile strength of 228 MPa, elastic modulus of 3.03 GPa, significant thermal mass loss at 330 ºC, and oxides formation during calcinations at 600 ºC and 650 ºC for pozzolana compounds. The endocarp has smooth, overlapping, consolidated layers, specific weight of 1.29 g/cm3, and mass loss at 339 ºC, with calcinations at 800 ºC. Regarding the mechanical test results of the mortar matrix, it was concluded that incorporating coconut fiber enhanced flexural strength. The base mortar (MB) sample reached a strength of 1.01 MPa, while the mix with 3% coconut fiber at 5cm length achieved 1.05 MPa. In terms of compressive strength, the MB sample was 6.21 MPa, while samples with 3% fiber at 3cm length reached a strength of 5.35 MPa, showing higher compressive strength in MB. The second composite material tested was the polymer matrix, where the combination of industrial wastes of low-density polyethylene, high-density polyethylene, and polypropylene yielded favorable results with coconut fiber incorporation. Flexural strength tests on MB were 13.05 MPa, and for mortar plus 20% coconut fiber, it was 17.37 MPa; compression test results for MB were 19.31 Mpa, and for mortar with 25% fiber incorporation, the compressive strength was 21.79 MPa. These results confirmed that coconut fiber enhances tensile and compressive strengths in polymer matrices.