Geopolymers are green materials with three-dimensional silicon and aluminum tetrahedral structures that can be serving as environmentally friendly construction materials and therefore have the potential to contribute to sustainable development. In this paper, the mechanism and research progress regarding the carbonation resistance, structural fire resistance, corrosion resistance, permeation properties and frost resistance of geopolymer concretes are reviewed, and the main problems with the durability of geopolymer concretes are discussed. Geopolymers possess the superb mechanic property and their compression strengths could be higher than 100 MPa. Generally, the higher the GPC strength, the better the carbonation-resistant. GPC has excellent fire resistance, due to geopolymers are acquired an inorganic skeleton which is affected by the alkali content, alkali cation, and Si/Ai ratio. There are a large number of Al-O and Si-O structures in geopolymers. Geopolymers do not react with acids at room temperature and can be used to make acid-resistant materials. Besides, GPC owning low porosity volume shows good resistance to permeability. The freezing-thawing failure mechanism of geopolymer concretes is mainly based on hydrostatic and osmotic pressure theory. GPC has poor frost resistance, and the freezing-thawing limit is less than 75 times.

Compared to thermosetting resins, thermoplastic polymers offer many advantages as fiber reinforced composite matrices, such as excellent toughness, superior corrosion resistance, weldability, and recyclable, etc. However, the processibility of thermoplastic composites is commonly considered as a challenge because of the high viscosity of polymer melts (e.g., polypropylene, polyetheretherketone, etc.), which remarkably hinders their applications. Using low viscosity and in situ polymerizable thermoplastic resins to manufacture continuous fiber reinforced thermoplastic composites have been deemed as a cost-effective emerging approach to surpass the processibility challenges. Therefore, this paper presents an overview of advancement in the engineering, high-performance and room-temperature-processible liquid methyl methacrylate (MMA) resins and their composites up to date. First, the polymerization behavior and kinetic modeling of the MMA resins are reviewed, and the effects of initiators on the polymerization are summarized. In the second part, the pultrusion process and modeling including impregnation, temperature distribution and pulling force are discussed. Next, the mechanical properties and durability of the carbon fiber-, glass fiber-reinforced MMA-matrix composites are presented. Finally, the challenges of the preparation and application of the MMA-matrix composites are identified.

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