## 1 Introduction
#### Literature Review on Mortars with Natural Fibers: Coconut, Abaca and Toquilla
\begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Ref.** & **Fiber Addition** & **Fiber Length [mm]** & **Main Results** \\ \hline
[22] & 0, 4, 6, and 8\% by weight of cement & 16.7 & In all cases the flexural strength was increased, however, for the compressive strength a decrease was observed from 4\% added fiber. Capillary water absorption in the mortars is increased. Energy consumption and CO\({}_{2}\) emissions during production decreased by more than 11\% compared to the control mortar without coconut fiber. \\ \hline
[23] & 0, 0.2, 0.4, and 0.6\% mass fractions of cement and soil mix & 24.0 & The coconut fiber reinforcement increased mortar blocks’ residual strength under compression, as well as their ductility and energy absorption. In addition, a significant improvement in mortar durability against freeze–thaw and moisture–dryness cycles was obtained. \\ \hline
[24] & 0.5, 1.0, 1.5, and 2.0\% relative to the weight of cement & 30.0 & Properties of cement mortars with coconut fiber in masonry walls were evaluated. The best results were obtained for addition of 0.5\% fiber, significantly improving flexural strength and slightly increasing diagonal compression in walls. \\ \hline
[25] & 0, 0.25, 0.5, 1.0, 1.25 and 1.5\% by volume & Less than 3.0 & As the interface between added fibers and mortar matrix weakened, there was an improvement in the mortars’ cushioning properties. However, there was a compressive strength loss and an increase in porosity. \\ \hline
[26] & 0.125, 0.25, 0.5 and 0.75 by weight of mortar mix & 24.0 & While there was no significant improvement in flexural and compressive mechanical strengths, post-cracking properties such as ductility, residual strength and toughness increased with a higher fraction of coconut fiber in the mortar matrix. \\ \hline
[27] & 0, 1, 2.5, and 4\% by volume & 17.0 & Coconut fiber addition positively influenced the first crack deflection, improving the toughness indices, plastic cracking and impact strength of the produced cementitious mortars. \\ \hline
[28] & 0, 1, 2 and 3\% by volume of mortar & 10.0–20.0 & The best results were obtained with additions of coconut fiber at 2\% by volume of mortar, significantly increasing flexural strength compared to the reference, improving toughness, and preventing cracking. \\ \hline
[29] & 0, 1, 2 and 3\% by volume of mortar & 16.0–18.0 & The mortars were subjected to moisture–dryness cycles and an increase in wetting was observed in coconut fiber samples. Natural degradation of the fibers in the mortar matrix occurred, which decreased the mechanical strengths. \\ \hline
[30] & 1.5\% by volume of mortar & 15.0 & Higher flexural strengths, increased fracture energy and increased capillary water absorption were obtained compared to traditional mortar. \\ \hline
[31] & 0, 5, 10, 15, and 20\% by weight of cement & 60.0 & The potential use of coconut fiber reinforced mortars as a facade cladding material was analyzed. It was found that these mortars with plant fibers could reduce dwelling interior temperatures by 0.5–1.5 \({}^{\circ}\)C. \\ \hline
[32] & 0.25 and 0.5\% by weight of cement & More than 10 & The coconut fiber reinforced mortars significantly improved flexural and compressive mechanical strengths, satisfying the criteria for application as mortar in masonry walls according to Colombian standards. \\ \hline
[33] & 0, 3, 6, 9, 12, and 15\% by weight of cement & 10.0–30.0 & Composite with a combination of 10\% silica fume, 10\% metakaolin and 6\% coconut fibers showed superior mechanical and physical properties to the reference mortar, with a compact microstructure, making it a sustainable and environmentally friendly alternative. \\ \hline  & & & \\ \hline  & & & \\ \end{tabular} Note: Search in Web of Science with the keywords: ((“Coco” OR “Coconut”) AND (“Fiber\"\" OR “Fiber\"\") AND (“Mortar\"\")).  
\end{table} 
Table 1: Coconut fiber-reinforced cement mortar studies. their thermal resistance [31] and the durability of these cement composites [23].