Geopolymer materials have been gaining ground in the civil construction sector not only for having superior physical properties when compared to conventional cement, but also for being less harmful to the environment, since the synthesis of the geopolymer does not release toxic gases or require high energy costs. On the other hand, geopolymer materials like cementitious matrices have low flexural strength and have fragile breakage. To overcome these deficiencies, the insertion of fibers in geopolymeric matrices has been evaluated as a solution. Although most research on this practice focuses on the use of synthetic fibers, the use of natural fibers has been growing and brings as an advantage the possibility of producing an even more ecological material, satisfying the need to create eco-friendly materials that exists today in society. Thus, this paper aimed to, through the evaluation of research available in the literature, understand the behavior of fibers in geopolymer matrices, identify similarities and differences between the performance of geopolymer composites reinforced with natural and synthetic fibers and, understanding that it is possible, point out ways to optimize the performance of these composites.

https://www.mdpi.com/2073-4360/13/15/2493/pdf

Natural Fibers as an Alternative to Synthetic Fibers in Reinforcement of Geopolymer Matrices: A Comparative Review.

Synergic effects of cellulose nanocrystals and alkali on the mechanical properties of sisal fibers and their bonding properties with epoxy Part A Applied science and manufacturing

With an embodied carbon content of 0.93 kg CO2/kg, cement is an essential component of concrete. As the global demand for concrete construction is rising, research is being conducted to replace cement with supplementary cementitious materials (SCMs). A variety of SCMs are identified as having positive impacts on the concrete's compressive strength and embodied carbon. Coir Fibre Ash (CFA) is well known in SCM from existing research, but its use in concrete has not been investigated from an embodied carbon perspective before. The paper adopts an experimental methodology involving CFA as SCM at 3%, 6%, 9%, 12%, 15%, and 18% of 576 kg cement for each m3 of concrete. CFA was therefore added. The study aimed to find out the impact of the addition of CFA in concrete on compressive strength (CS), flexural strength (FS), splitting tensile strength (STS), and modulus of elasticity (MOE). The determination of embodied carbon was made, and RSM was used to develop the model with maximum accuracy. Samples were prepared for 7, 14, and 28 days. CFA was found to be positively affecting CS, FS, STS, and MOE till 9%, after which, because of the dominance of silica dioxide in CFA, it did not show any improvement. Embodied carbon was found to be decreasing with the increasing addition of CFA. RSM results followed by optimization provided highly validated equations for predicting the CS, FS, STS, and MOE of concrete by just using the value of CFA as SCM. 

Effect of Coir Fibre Ash (CFA) on the strengths, modulus of elasticity and embodied carbon of concrete using response surface methodology (RSM) and optimization

Effect of Alkali Treatment on Physical-Chemical Properties of Sisal Fibers and Adhesion Towards Cement-Based Matrices

Based on the Glivenko-Cantelli theorem and Weibull distribution functions, the fatigue life of foam concrete with different sisal fibre volume fraction (0–0.3% vol.) was performed. When the two-parameter Weibull function was selected, a linear regression analysis showed that the fatigue life had high correlation between the independent and dependent variables (correlation coefficients above 0.75). But the three-parameter Weibull analysis gave more accurate results (correlation coefficients above 0.90). Then, the corresponding Weibull probability density function distributions of the fatigue lives were compared. Based on the parameters obtained, the fatigue lives of foam concrete with different survival probabilities were analyzed and compared with results taken from the literature. Finally, for specific survival probabilities, the fatigue limit and fatigue life of foam concrete under specified stress level were predicted. 

Parameters estimation and fatigue life prediction of sisal fibre reinforced foam concrete

This review article focused on the mechanical properties of sisal, coir and hemp fiber-reinforced concrete composites and several factors affecting the mechanical properties of natural fiber-reinfo...

A Review on Chemical Modification by using Sodium Hydroxide (NaOH) to Investigate the Mechanical Properties of Sisal, Coir and Hemp Fiber Reinforced Concrete Composites

Nipapan Kanjana

Papers

A Review on Chemical Modification by using Sodium Hydroxide (NaOH) to Investigate the Mechanical Properties of Sisal, Coir and Hemp Fiber Reinforced Concrete Composites