Water and waterglass mixtures for foam glass production

The present study investigates the use of sodium waterglass as an environmental friendly foaming agent to create fine porous foam glasses. The reactivity of the foaming agent was determined using thermogravimetrical measurements and difference scanning calorimeter analysis. The porosity of the foam glasses was measured and the pore morphology was evaluated using scanning electron microscopy. Phase formation caused by the addition of waterglass was studied using X-ray diffraction. Furthermore, thermal conductivity and splitting tensile strength of the materials were measured. Foaming by using only waterglass as foaming agent is possible. As a result, fine porous foam glasses with closed pores of 4 nm to 800 µm in diameter and mechanical strengths of 1.7 N/mm2 could be obtained. Conventional foam glasses which are available on the market have bigger pore sizes up to 3 mm and achieve lower strength. For this reason the produced foam glass can be used as a promising light weight construction material.