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Currently, novel inorganic alumino-silicate materials, known as geopolymer composites, have emerged swiftly as an ecobenevolent alternative to contemporary ordinary Portland cement (OPC) building materials since they display superior physical and chemical attributes with a diverse range of possible potential applications. The said innovative geopolymer technology necessitates less energy and low carbon footprints as compared to OPC-based materials because of the incorporation of wastes and/or industrial byproducts as binders replacing OPC. The key constituents of ceramic are silica and alumina and, hence, have the potential to be employed as an aggregate to manufacture ceramic geopolymer concrete. The present manuscript presents a review of the performance of geopolymer composites incorporated with ceramic waste, concerning workability, strength, durability, and elevated resistance evaluation.

This paper elucidates the mechanical performance, microstructure, and porosity evolution of fly ash geopolymer after 10 years of curing age. Given their wide range of applications, understanding the microstructure of geopolymers is critical for their long-term use. The outcome of fly ash geopolymer on mechanical performance and microstructural characteristics was compared between 28 days of curing (FA28D) and after 10 years of curing age (FA10Y) at similar mixing designs. The results of this work reveal that the FA10Y has a beneficial effect on strength development and denser microstructure compared to FA28D. The total porosity of FA10Y was also lower than FA28D due to the anorthite formation resulting in the compacted matrix. After 10 years of curing age, the 3D pore distribution showed a considerable decrease in the range of 5–30 µm with the formation of isolated and intergranular holes.

This study examines the strength development of fly ash-based geopolymer (FAG) as a stabilizer for road base material for pavement construction. In the last decade, there has been a rapid development of conventionally treated bases, such as cement-treated bases. However, a major problem with this kind of application is the shrinkage cracking in cement-treated bases that may result in the reflection cracks on the asphalt pavement surface. This study explores the effects of FAG on base layer properties using mechanistic laboratory evaluation and its practicability in pavement base layers. The investigated properties are flexural strength (FS), unconfined compressive strength (UCS), shrinkage, and resilient modulus (RM), as well as indirect tensile strength (ITS). The findings showed that the mechanical properties of the mixture enhanced when FAG was added to 80–85% of crushed aggregate, with the UCS being shown to be a crucial quality parameter. The effectiveness of FAG base material can have an impact on the flexible pavements’ overall performance since the base course stiffness directly depends on the base material properties. As a stabilizing agent for flexible pavement applications, the FAG-stabilized base appeared promising, predicated on test outcomes.

This paper details a finite element analysis of the behaviour of Si-Al geopolymer concrete beam reinforced steel bar under an impulsive load and hyper velocity speed up to 1 km/s created by an air blast explosion. The initial torsion stiffness and ultimate torsion strength of the beam increased with increasing compressive strength and decreasing stirrup ratio. The study involves building a finite element model to detail the stress distribution and compute the level of damage, displacement, and cracks development on the geopolymer concrete reinforcement beam. This was done in ABAQUS, where a computational model of the finite element was used to determine the elasticity, plasticity, concrete tension damages, concrete damage plasticity, and the viability of the Johnson-Cook Damage method on the Si-Al geopolymer concrete. The results from the numerical simulation show that an increase in the load magnitude at the midspan of the beam leads to a percentage increase in the ultimate damage of the reinforced geopolymer beams failing in shear plastic deformation. The correlation between the numerical and experimental blasting results confirmed that the damage pattern accurately predicts the response of the steel reinforcement Si-Al geopolymer concrete beams, concluded that decreasing the scaled distance from 0.298 kg/m3 to 0.149 kg/m3 increased the deformation percentage.

Zeolite has been successfully synthesized from clay and rice husk ash in the form of powder by using the hydrothermal method with variations in chemical compositions of alkaline solution and the amount of rice husk ash. The clay raw material was obtained from the Sidrap area of South Sulawesi and rice husk ash is obtained from the burning pile of rice husks. Sidrap clay and rice husk ash were activated using an alkaline solution of NaOH and varied rice husk ash and the addition of AlCl3. The addition of AlCl3, an alkaline solution of NaOH and H2O was used in the amount of 25.5 grams and variations of rice husk ash were 2.5 grams and 6.5 grams. Meanwhile, without the addition of AlCl3, an alkaline solution of NaOH and H2O was used for 20.5 grams and variations of rice husk ash from 2.5 grams and 6.5 grams. Then the mixture was then put into an autoclave with a temperature of 100°C for 3 hours. The basic material used in the manufacture of zeolite is carried out by X-ray Fluorescence (XRF) characterization to determine the constituent elements of basic material, which showed the content of SiO2 was 45.80 wt% in the clay and 93.40% in the rice husk ash. The crystalline structure of the zeolite formed was characterized by X-Ray Diffraction (XRD). It was found the resulting zeolite were identified as Zeolite-Y, Hydrosodalite, and ZSM-5. The microstructure properties of the resulting zeolite were determined by using Scanning Electron Microscopy (SEM).

This paper presents an experimental investigation on the mechanical properties and microstructure of geopolymer repair materials mixed using fly ash (FA) and concrete substrates. An optimal combination of FA and concrete substrate was determined using the compressive test of geopolymer mortar mixed with various concrete substrate classes. It was found that the contribution of (C35/45) concrete substrates with the FA geopolymer mortar increases the 28-day bonding strength by 25.74 MPa. The microstructure analysis of the samples using scanning electron microscopy showed the denser structure owing to the availability of high calcium and iron elements distribution. These metal cations (Ca2+ and Fe3+) are available at OPC concrete substrate as a result from the hydration process reacted with alumina-silica sources of FA and formed calcium aluminate silicate hydrate (C-A-S-H) gels and Fe-bonding linkages.

Dolomite can be used as a source of aluminosilicate to produce geopolymers; however, this approach is limited by its low reactivity. This study analyzes the viability of producing geopolymers using dolomite/fly-ash with sodium silicate and NaOH solutions (at multiple concentrations) by determining the resultant geopolymers’ compressive strengths. The dolomite/fly-ash-based geopolymers at a NaOH concentration of ~22 M resulted in an optimum compressive strength of 46.38 MPa after being cured for 28 days, and the SEM and FTIR analyses confirmed the denser surface of the geopolymer matrix. The synchrotron micro-XRF analyses confirmed that the Ca concentration exceeded that of Si and Mg, leading to the formation of calcium silicate hydrate, which strengthens the resulting geopolymers.

The main objective of this research was to investigate the influence of curing temperature on the phase transformation, mechanical properties, and microstructure of the as-cured and sintered kaolin-ground granulated blast furnace slag (GGBS) geopolymer. The curing temperature was varied, giving four different conditions; namely: Room temperature, 40, 60, and 80 °C. The kaolin-GGBS geopolymer was prepared, with a mixture of NaOH (8 M) and sodium silicate. The samples were cured for 14 days and sintered afterwards using the same sintering profile for all of the samples. The sintered kaolin-GGBS geopolymer that underwent the curing process at the temperature of 60 °C featured the highest strength value: 8.90 MPa, and a densified microstructure, compared with the other samples. The contribution of the Na2O in the geopolymerization process was as a self-fluxing agent for the production of the geopolymer ceramic at low temperatures.

The density, compressive strength, and thermal insulation properties of fly ash geopolymer paste are reported. Novel insulation material of glass bubble was used as a replacement of fly ash binder to significantly enhance the mechanical and thermal properties compared to the geopolymer paste. The results showed that the density and compressive strength of 50% glass bubble was 1.45 g/cm3 and 42.5 MPa, respectively, meeting the standard requirement for structural concrete. Meanwhile, the compatibility of 50% glass bubbles tested showed that the thermal conductivity (0.898 W/mK), specific heat (2.141 MJ/m3K), and thermal diffusivity (0.572 mm2/s) in meeting the same requirement. The improvement of thermal insulation properties revealed the potential use of glass bubbles as an insulation material in construction material.

Due to the extraordinary properties for heavy-duty applications, there has been a great deal of interest in the utilization of waste material via geopolymerization technology. There are various advantages offered by this geopolymer-based material, such as excellent stability, exceptional impermeability, self-refluxing ability, resistant thermal energy from explosive detonation, and excellent mechanical performance. An overview of the work with the details of key factors affecting the heavy-duty performance of geopolymer-based material such as type of binder, alkali agent dosage, mixing design, and curing condition are reviewed in this paper. Interestingly, the review exhibited that different types of waste material containing a large number of chemical elements had an impact on mechanical performance in military, civil engineering, and road application. Finally, this work suggests some future research directions for the the remarkable of waste material through geopolymerization to be employed in heavy-duty application.