Mechanical properties and durability of fiber reinforced geopolymer composites: A review on recent progress

Abstract

Geopolymer concrete has similar mechanical properties to ordinary Portland cement (OPC) concrete, and even better properties in high temperature, high corrosion environment. However, geopolymer still has the disadvantages of large shrinkage and high brittleness, which greatly limit its application. Fiber reinforcement is widely used in various geopolymer systems to overcome the brittleness issue, but still retains the high strength. Over the past 10 years, great progress has been made in the research of fiber reinforced geopolymers in the aspect of toughening efficiency and durability improvement. Many studies have been conducted on fiber reinforced geopolymers, but there are still few systematic summaries on the addition of inorganic fibers and organic fibers to geopolymers. What is more there are many novel studies such as the application of geopolymers to 3D printing and the new concept of fiber factor have not been reviewed. In this paper, inorganic fibers, natural fibers and synthetic fibers in geopolymers are briefly reviewed, and their specific effects on geopolymers' compressive, flexural, tensile strength, fracture toughness, shear strength and durability such as shrinkage, chemical resistance, freeze–thaw resistance are reviewed. The current understanding of bonding mechanism and fiber‐geopolymer interface are also discussed, and related knowledge gaps and future work challenges are correspondingly pointed out.

Thermal Properties of Eco-Friendly Earthen Materials Stabilized with Bio-Based Polymers: Experimental Data and Modeling Procedure for Improving Mix-Design

“…In the case of sulfoaluminate cements, the disadvantages are represented by their overly short setting time [ 13 ], low PH values [ 14 ], expansion phenomena [ 15 ], and high cost [ 16 ]. On the other hand, for geopolymers, the drawbacks could be their large shrinkage, high brittleness [ 17 ], and mechanical properties, which decrease as a function of time [ 12 , 18 ]. Additionally, the limited familiarity among designers with these types of materials, and their often higher cost compared to Portland cement, restrict their use [ 11 ].…”

The Different Properties of Geopolymer Composites Reinforced with Flax Fibers and Carbon Fibers

“…One of the main defects of geopolymers, which limits their current application, is that under adverse environmental conditions, these materials are prone to the formation of microcracks [8,9]. These microcracks may eventually coalesce, forming one or more macroscopic cracks, which can propagate and lead to structural damage.…”

“…Due to this, carbon fiber (CF)-reinforced geopolymers are attracting increasing scrutiny from researchers, who have noted the ability of CFs to control macroscopic crack propagation through the bridging effect, delaying the initiation and expansion of microcracks and improving splitting tensile strength. Hence, a comprehensive investigation of CF-reinforced geopolymers is imperative for advancing the field [8,9].…”

“…In particular, in the area of mechanical properties, the tensile strength, ductility, and impact strength were significantly improved. The hybridization of geopolymers is therefore proving to be a promising field of research [9,10]. It has been shown that unreinforced geopolymers have a brittle structure, which leads to their use in relatively few applications [11,12].…”