Geopolymers: new products for sustainability of the environment

Geopolymerization is the process of polymerizing minerals with high silica and alumina at low temperature by the use of alkali solutions. Geopolymers could be a substitute for Portland cement and for advanced composite and ceramic applications. The geopolymer technology would eliminate the need for energy requirement as they may be cured at ambient temperature.
Current research at the University of Jordan concentrates on developing building products (geopolymers) through geopolymerization. The goal is to produce low cost construction materials for green housing. The produced construction materials are characterized by high strength, high heat resistance, low production cost, low energy consumption, and low CO2 emissions. The compressive strength of the produced geopolymers has indicated promising results for both dry and wet specimens after optimizing the mixing ratios of the filler, water, and NaOH.
The results have confirmed that natural kaolinite satisfy the criteria to be used as a precursor for the production of high quality inexpensive, stable materials. Geopolymeric products gave a high unconfined compressive strength values (> 52 MPa) for dry test. This value has been increased by the immersion of the geopolymerzed products in 10% solution of triethylene glycol.
The addition of rock wool gave the maximum unconfined compressive strength up to 90 MPa after heating to 500 °C for one day. The produced geopolymers proved to be highly durable under different physical and chemical conditions. The physical properties suit its use in green housing and restoration of archaeological sites.
The addition of zeolitic tuff as a filler has increased the adsorption capacity of the polymerized products towards heavy metals. This result enables the use of geopolymers in waste water treatment plants.