The Mechanical Properties of Plant Fiber-Reinforced Geopolymers: A Review

Self Cite

Plant fibers (PFs), such as hemp, Coir, and straw, are abundant in resources, low in price, light weight, biodegradable, have good adhesion to the matrix, and have a broad prospect as reinforcements. However, the degradation of PFs in the alkaline matrix is one of the main factors that affects the durability of these composites. PFs have good compatibility with cement and the geopolymer matrix. They can induce gel growth of cement-based materials and have a good toughening effect. The water absorption of the hollow structure of the PF can accelerate the degradation of the fiber on the one hand and serve as the inner curing fiber for the continuous hydration of the base material on the other. PF is easily deteriorated in the alkaline matrix, which has a negative effect on composites. The classification and properties of PFs, the bonding mechanism of the interface between PF reinforcements and the matrix, the water absorption of PF, and its compatibility with the matrix were summarized. The degradation of PFs in the alkaline matrix and solution, drying and wetting cycle conditions, and high-temperature conditions were reviewed. Finally, some paths to improve the alkaline degradation of PF reinforcement in the alkaline matrix were proposed.

Section: The Path To Slow Fiber Degradationmentioning

confidence: 99%

Alkaline Degradation of Plant Fiber Reinforcements in Geopolymer: A Review

Liu

2023

Self Cite

“…PFs are very prone to alkaline degradation in the cement-based material matrix, while the degradation degree of PFs in the GP matrix is much lower [ 72 ]. The composite of PFs and GPs can overcome the disadvantage of poor durability caused by fiber degradation of composite materials, and its performance is better than that of PF-reinforced cement-based composite materials in some respects [ 73 , 74 ]. GPs not only have the advantages of low cost, environmental friendliness, and relatively low energy consumption, but they also have good compressive strength, durability, and heat resistance, as well as high fire and heat resistance [ 75 ].…”

Section: Plant Fiber-reinforced Geopolymers (Pfrgs)mentioning

confidence: 99%

Effect of Plant Fiber on Early Properties of Geopolymer

Lv,

Wu,

Guo

et al. 2023

Self Cite

Geopolymer (GP) is environmentally friendly, has good mechanical properties and long-term workability, and has broad application prospects. However, due to the poor tensile strength and toughness of GPs, they are sensitive to microcracks, which limits their application in engineering. Fiber can be added to GPs to limit the growth of cracks and enhance the toughness of the GP. Plant fiber (PF) is cheap, easy to obtain, and abundant in source, which can be added to GP to improve the properties of composites. This paper reviews recent studies on the early properties of plant fiber-reinforced geopolymers (PFRGs). In this manuscript, the properties of PFs commonly used for GP reinforcements are summarized. The early properties of PFRGs were reviewed, including the rheological properties of fresh GPs, the early strength of PFRGs, and the early shrinkage and deformation properties of PFRGs. At the same time, the action mechanism and influencing factors of PFRGs are also introduced. Based on the comprehensive analysis of the early properties of PFRGs, the adverse effects of PFs on the early properties of GPs and the solutions were summarized.

“…[38]. According to different types and parts of plants, NCFs commonly used for geopolymer reinforcement can be divided into bast fibers, leaf fibers, fruit fibers, seed fibers, and stem fibers [39]; their concise classification is shown in Figure 1. According to Lv et al [11], NCFs composed of cellulose, hemicellulose and lignin have unique microstructure.…”

Section: Classification and Properties Of Ncfsmentioning

confidence: 99%

Effect of Wet–Dry Cycling on Properties of Natural-Cellulose-Fiber-Reinforced Geopolymers: A Short Review

Lv,

He,

Pang

et al. 2023

Self Cite

To study the long-term properties of cement-based and geopolymer materials exposed to outdoor environments, wet–dry cycles are usually used to accelerate their aging. The wet–dry cycling can simulate the effects of environmental factors on the long-term properties of the composites under natural conditions. Nowadays, the long-term properties of geopolymer materials are studied increasingly deeply. Unlike cement-based materials, geopolymers have better long-term properties due to their high early strength, fast hardening rate, and wide range of raw material sources. At the same time, natural cellulose fibers (NCFs) have the characteristics of abundant raw materials, low price, low carbon, and environmental protection. The use of NCFs as reinforcements of geopolymer matrix materials meets the requirements of sustainable development. In this paper, the types and properties of NCFs commonly used for geopolymer reinforcement and the polymerization mechanism of geopolymer matrix materials are summarized. By analyzing the properties of natural-cellulose-fiber-reinforced geopolymers (NCFRGs) under non-wet–dry cycles and NCFRGs under wet–dry cycles, the factors affecting the long-term properties of NCFRGs under wet–dry cycles are identified. Meanwhile, the degradation mechanism and mechanical properties of NCFRG composites after wet–dry cycles are analyzed. In addition, the relationship between the properties of composites and the change of microstructure of fiber degradation is further analyzed according to the results of microscopic analysis. Finally, the effects of wet–dry cycles on the properties of fibers and geopolymers are obtained.