The production of agricultural residues causes environmental pollution, especially in regions with intensive horticultural production. The solution is to maximise the use of residues, applying the 'zero waste' model and using them to develop construction materials. Natural fibres used to reinforce materials have environmental and economic benefits due to their low cost. This research presents an innovative characterisation using an inverted-plate optical microscope, a high-resolution scanning electron microscope (HRSEM) and a 3D X-ray microscope. A physico-mechanical and chemical characterisation of horticultural fibres was also conducted. The fibres analysed were those produced in the highest quantities, including those from tomatoes, peppers, zucchinis, cucumbers and aubergines. The viability of these natural fibres for use as reinforcements in biocomposites was investigated. The analysis centred on studying the microstructure, porosity, chemical composition, tensile strength, water absorption and environmental degradation of the natural fibres. The results showed a porosity ranging from 47.44% to 61.18%, which contributes to the lightness of the materials. Cucumber stems have a higher tensile strength than the other stems, with an average value of 19.83 MPa. The SEM analysis showed a similar chemical composition of the scanned fibres. Finally, the life cycle of the materials made from horticultural residue was analysed, and negative GWP (global warming potential) CO2eq values were obtained for two of the proposed materials, such as stabilised soil reinforced with agricultural fibres and insulation panels made of agricultural fibres.

This study introduces N-MBER, a novel soil stabilizer incorporating nano-SiO2, which significantly enhances the strength of cement-based soil mixtures. Experimental results show that N-MBER exhibits an exponential increase in strength over time, with strength improvements ranging from 15% to 50% compared to conventional stabilizers, depending on the nano-SiO2 content. The primary mechanism driving this enhancement is the increased formation of calcium silicate hydrate (C-S-H) gel, which contributes to improved durability and load-bearing capacity. Additionally, the nano-SiO2 improves particle structure, leading to greater overall stability. These advancements suggest that N-MBER not only improves soil stabilization but also has potential for reducing waste by minimizing reliance on traditional cement-based stabilizers. This development offers valuable insights into soil treatment techniques and presents a sustainable solution for infrastructure projects where soil strength is critical.

An industrial waste survey was performed in the city of Bahia Blanca (Argentina) to analyse the possibility of disposal in a cement matrix. A molecular sieve (MS), from a gas transportation company was found and studied. This granular material is used in absorption towers to filter the hydrocarbons contained in the gas and it is disposed in a safe landfill at the end of its useful life. The objective of the current paper is mainly focused on the feasibility of recycling milled molecular sieves on cement mortars with its incorporation and comparing them with a standard sample (without waste). For MS, bulk density, specific gravity, water absorption, particle size distribution, and X-ray diffraction were tested. Mixes were made by incorporating 0%, 15%, and 25% of milled molecular sieves by weight of cement, to evaluate hydration process at different ages by calorimetry, puzzolanic effect by Frattini test and measure mechanical properties in mortars employing standardized tests. In addition, a leachate analysis of curing water was conducted after 90 days for contaminants. The incorporation of milled molecular sieves in cement mortars produces changes in the properties of the mixture at early ages but the reduction of compressive strength decreases over time. It is concluded that this is a potential alternative to the final disposal of these wastes without harming the environment and has a possible pozzolanic effect on the mixtures.