This research suggested natural hemp fiber-reinforced ropes (FRR) polymer usage to reinforce recycled aggregate square concrete columns that contain fired-clay solid brick aggregates in order to reduce the high costs associated with synthetic fiber-reinforced polymers (FRPs). A total of 24 square columns of concrete were fabricated to conduct this study. The samples were tested under a monotonic axial compression load. The variables of interest were the strength of unconfined concrete and the number of FRR layers. According to the results, the strengthened specimens demonstrated an increased compressive strength and ductility. Notably, the specimens with the smallest unconfined strength demonstrated the largest improvement in compressive strength and ductility. Particularly, the compressive strength and strain were enhanced by up to 181% and 564%, respectively. In order to predict the ultimate confined compressive stress and strain, this study investigated a number of analytical stress–strain models. A comparison of experimental and theoretical findings deduced that only a limited number of strength models resulted in close predictions, whereas an even larger scatter was observed for strain prediction. Machine learning was employed by using neural networks to predict the compressive strength. A dataset comprising 142 specimens strengthened with hemp FRP was extracted from the literature. The neural network was trained on the extracted dataset, and its performance was evaluated for the experimental results of this study, which demonstrated a close agreement.

This paper presents an investigation reviewed on various research topics of the natural fibers in worldwide and Thailand. Practically, the traditional synthetic fibers for noise absorbed purpose are human and environmental harmful, thus the natural fibers might be the alternative way for consumers. The characteristics of natural fibers commonly are lightweight, high strength, but less pollution and low cost. Furthermore, the agriculture wastes would be value-added and reduced on the particulate matters (PM) 2.5 communities’ nuisance from the incineration affecting human health, environment and global warning in advance. In the present, the traditional materials using for noise absorbent are derived from synthetic fibers such as asbestos and fibers glass, mostly 20 - 45 % of asbestos fibers that World Health Organization (WHO) mentioned the hazard of asbestosis regarding on lung cancer, pleurisy lung cancer and ovarian cancer about 107,000 people per year. In general, the natural fibers are classified on 3 configurations: Cellular, fibrous and granular types which are their different properties on noise reduction. Also, this review particularly presents a sound absorption coefficient (SAC) that relates to the main importance factors (for example of physical, chemical, mechanical, etc.) including an analysis of the potential chances to utilize on the sustainability of these green natural materials, especially banana fibers in Thailand. HIGHLIGHTS Many natural fibers are used for noise control as an alternative to the traditional ones. Natural fiber composites appear to be cheaper, lighter, and more environmentally friendly than glass fiber composites Many fibrous materials (for example, rice straw, coconut coir, banana fibers, etc.) have shown good sound-absorbing properties and heat insulation as well The physical, chemical, and mechanical properties of banana fibers, including the content of cellulose and lignin, can influence the ductility and elongation values, especially in the cultivated banana type The development of banana fiber reinforced paper pulp bio-composites was observed for its sound absorption coefficient GRAPHICAL ABSTRACT

The present research study aims to investigate the properties and performance of concrete containing an integral crystalline waterproofing (ICW) admixture, added at an optimal dosage to resist water without compromising structural integrity. To achieve this, an experimental program was conducted on specimens with ICW dosage variations ranging from 0 to 4.8 kg/m2. The impact on water absorption, pulse velocity, and microstructural characteristics was tested and analyzed using XRF and EDS techniques. The findings reveal that increasing the dosage decreases water absorption by approximately 43% at maximum dosage compared with the control. A 41% increase in pulse velocity indicates a denser concrete matrix. The principle of optimization is highlighted, as an overdose of ICW generates a non-structural crystalline gel at the bottom of the specimens. The optimum dosage range for ICW to improve water resistance without adverse effects on structural performance was determined to be 3.2 to 4.0 kg/m2. This research introduces a novel approach by evaluating the comprehensive performance of concrete in relation to ICW dosage, providing valuable insights into the practical application of ICW admixture to enhance concrete quality and durability. Doi: 10.28991/CEJ-2024-010-10-02 Full Text: PDF