Abstract
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 results have confirmed that natural kaolinite satisfy the criteria to be used as a precursor for the production of high quality inexpensive, stable materials. The kaolinite geopolymer specimens from El-Hiswa deposits with compressive strength of 44.4MPa under dry conditions and 21.8 MPa under water immersed conditions were obtained by using around 16 % NaOH at 80 degrees C after 14 hours. At higher temperatures these geopolymers maintained or improved their mechanical and physical performance after heating up to 600 degrees C. At 400 degrees C the compressive strength was 52.1 MPa under dry conditions and was 39.1 MPa under water saturated conditions. At 1000 degrees C the mechanical strength was 15.1 MPa under dry conditions and was 10.5 MPa under water saturated conditions. The density of the geopolymers has dropped down at dry conditions from 2.02 at 80 degrees C to 1.93 at 1000 degrees C. The presence of two refractory phases' sodalite and mullite make them sufficiently refractory at 1000 degrees C. The lower densities at higher temperatures enable their use as an insulating material.