The Role of Inorganic Polymer Technology in the Development of ‘Green Concrete’

Alkali-activated materials

Effect of curing temperature on the development of hard structure of metakaolin-based geopolymer

Geopolymers are a class of aluminosilicate materials synthesized by alkaline or alkali-silicate activation of solid alumina- and silica-containing precursor materials at ambient or higher temperature. These products have highly significant commercial and technological potential, but the exact physicochemical nature of the geopolymeric binder phase has never before been determined. Through analysis of existing experimental results from the literature and comparison with related systems, in particular the hydrothermal synthesis of zeolites, geopolymeric binders are identified as being comprised of agglomerates of nanocrystalline zeolites compacted by an amorphous gel phase. The degree of crystallinity is largely determined by product formulation and synthesis conditions. Results from powder X-ray diffraction, microscopy, electron diffraction, mechanical strength testing, and calorimetry are analyzed and shown to be consistent with the theory presented. The implications of nanocrystallinity are discussed, an...

Do Geopolymers Actually Contain Nanocrystalline Zeolites? A Reexamination of Existing Results

In this Feature Article, we discuss recent developments of flame retardant polymers. Three approaches are considered: (i) inherently flame retardant polymers, (ii) chemically modified polymers and (iii) flame retardants as additives for polymers. We have tried to show the new directions and concepts emerging in the field of flame retardancy. We have mainly focused our comments on flame retardants, nanofillers and surface treatment because very promising concepts appeared recently in the published literature. Synergistic aspects are also fully discussed.

Fire retardant polymers : recent developments and opportunities

The fire response of a potassium aluminosilicate (Geopolymer) matrix carbon fiber composite was measured and the results compared to organic matrix composites being used for transportation, militar y, and infrastructure applications . At irradiance levels of 50 kW/m 2 typi- cal of the heat flux in a well developed fire, glass- or carbon-reinforced polyeste r, vinylester, epoxy, bismaleimde, cyanate ester, polyimide, phenolic, and engineering thermoplastic laminates ignited readily and released appreciable heat and smoke, while carbon-fiber reinforced Geopolymer com- posites did not ignite, burn, or release any smoke even after extended heat flux exposure . The Geopolymer matrix carbon fiber composite retains sixty-seven percent of its original flexural strength after a simulated large fire exposure.

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Fire resistant aluminosilicate composites

Mechanical properties of carbon composites made using an inorganic polymer

One of the major concerns in using Fiber Reinforced Composites in applications that might be subjected to fire is their resistance to high temperature. Some of the fabrics used in FRC, such as carbon, are fire resistant. However, almost all the resins used cannot withstand temperatures higher than 200{degrees}C. This paper deals with the development and use of a potassium aluminosilicate (GEOPOLYNER) that is inorganic and can easily sustain more than 1000{degrees}. The results presented include the composite behavior in tension, flexure, and shear. Tests have been conducted on the virgin samples and samples exposed to temperatures from 200 to 1000{degrees}. The results indicate that the composite can withstand 327, 245, and 14 MPa in tension, flexure, and shear respectively. It retains about 63 percent of its original flexural Strength at 800{degrees}. The fire response of the carbon fiber composite was measured and the results compared to organic matrix composites being used for infrastructure and transportation applications. At irradiance levels of 50 kW/m{sup 2} typical of the heat flux in a well developed fire, glass- or carbon-reinforced polyester, vinylester, epoxy, bismaleimde cyanate ester, polyimide, phenolic, and engineered thermoplastic laminates ignited readily and released appreciable heat and smoke, while carbon-fiber reinforcedmore » GEOPOLYNER composites did not ignite, bum, or release any smoke even after extended heat flux exposure.« less

Andrew J. Foden

Papers

Fire resistant aluminosilicate composites

Mechanical properties of carbon composites made using an inorganic polymer

Mechanical properties and fire response of geopolymer structural composites

Flexural fatigue properties of an inorganic matrix-carbon fiber composite