## 4 Conclusions  
In this research, the analysis and discussion were carried out with real reference data relating to the hypothetical production of a semi-rigid insulation building panel based on agricultural by-products, stabilised soil reinforced with fibres from agricultural by-product, as well as cement mortar reinforced also with agricultural fibres from intensive agriculture. To this end, the present study constitutes an innovative examination of the physical-mechanical properties of the agricultural by-product under consideration, with a particular emphasis on a detailed analysis of the microstructure of the fibres utilised. This analysis was conducted employing the inverted-plate optical microscope, and the porosity of the fibres was also studied for the purpose of calculating the lightening of the fibre-added construction materials. This was achieved by means of the 3D X-ray microscope. In addition, the use of the high-resolution scanning electron microscope (HRSEM) allowed the detection of crystallisations in the samples and the study of the chemical elements present in the agricultural by-product. The results of this experimental study led to the following conclusions:  
* The agricultural by-product studied exhibited a high water absorption range, between 197.42 \(\pm\) 1.57% and 268.57 \(\pm\) 2.03%. On average, residues from the Cucurbitaceae plant family, such as cucumber and zucchini, had a 13.5% higher absorption capacity than the Solanaceae plant family. * Cucumber fibres were found to demonstrate a maximum tensile strength of 19.83 MPa. This by-product had smaller diameter stems than the other typologies, which facilitated a better distribution of the applied tensile force across the section (i.e., its microstructure) and length of the stem. This resulted in the stem functioning as a whole and not weakening in specific areas, which would otherwise have affected its mechanical performance. * The porosity of the fibres under consideration ranged from 47.44% to 60.36% within the Solanaceae plant family and from 55.89% to 61.18% within the Cucurbitaceae plant family. Porosity is a determining factor in the calculation of the lightening of the construction materials developed with the use of these fibres. * The analysis of crystallisations in the plant structures of the agricultural by-products studied by HRSEM scanning revealed the presence of chemical elements. These elements were attributed to the fertilisers employed in intensive agriculture, as well as to the nutrients presented in the soil in which the plants were cultivated. It is important to consider their presence in order to specify the optimal use of the building materials to be developed. * The use of agricultural by-products as a reinforcement material for stabilised soil and for use as a semi-rigid panel offered significant ecological benefits, attaining negative GWP values of \(-\)67.036 kg/m\({}^{3}\) CO\({}_{2}\) equivalent and \(-\)1.104 kg/m\({}^{2}\) CO\({}_{2}\) equivalent, respectively. Cement mortar reinforced with the agriculture by-product achieved a GWP value of 3.862 kg/m\({}^{2}\) CO\({}_{2}\) equivalent. * The comprehensive characterisation of agricultural fibres presented in the current manuscript has a direct impact on the development of materials from these by-products. In consideration of this aforementioned characterisation, a specific plan for the development of materials from agricultural fibres can be formulated. A consistent planning includes the following aspects:
* The implementation of various pre-soaking techniques on fibres must be considered, given their high water absorption capacity. This can potentially impact the workability of the mixture and the mechanical properties of the developed material. * An analysis of fibre-reinforced material cracking and its ductile behaviour is also necessary. * A microstructure analysis of fibre-reinforced materials exposed to weathering or high moisture and temperature oscillations is required.