Study On Preparation And Lightening Of Non-metallic Geopolymer Materials

Non-metallic geopolymer is a new type of inorganic cementing materials which is synthesized mainly from aluminum silicate mineral materials or industrial solid waste, and has many advantages such as good mechanical property, high temperature resistant performance, low energy consumption, this material is extensively used for building material, fire-resistant insulation materials, desalination of sea water and so on.Geopolymer materials were prepared from fly ash and metakaolin as the main raw material, zeolite and clay as auxiliary material under the activation of sodium silicate. The optimized processing condition was determined considering the compressive strength and density of the products as the main criterion. Lightweight geopolymer materials was made from foaming agent and light aggregate; The influence of sodium silicate, water-solid ratio, curing condition, and admixture, aggregate and content were studied in this article.Results showed that the component of lime content of3%, water-solid ratio of3%and sodium silicate modulus of2.3was optimal choice, under the natural conditions, compressive strength of products only is14.4MPa when curing28d, acid resistance and high temperature resistant performance is poor; Under low temperature wet curing conditions, the optimized conditions are curing temperature of80℃, humidity of95%, curing time of120h and compressive strength of products is41.2MPa, products were soaked in0.5mol/L sulfuric acid solution for24h and mass loss is4%, calcined at the temperature of950℃for2h and the remaining rate of compressive strength is52.5%; Under cross curing conditions, the optimized conditions are curing temperature of80℃, humidity of95%, curing time of72h, autoclaved curing at0.8MPa for8h and products of compressive strength is62.8MPa, products were soaked in0.5mol/L sulfuric acid solution for24h and mass loss is2.7%, calcined at the temperature of950℃for2h and the remaining rate of compressive strength is80.7%.During the foamed lightweight geopolymer materials preparation, the aluminum amount should be controlled in0.3-0.4%, foaming temperature should be controlled in35-40℃; Water-solid ratio should be controlled in0.37-0.43, the dosage of Na2O in6%-8%was more appropriate, modulus of sodium silicate in2.0-2.5was relatively suitable, the optimum content of sodium hexametaphosphate was0.3%, and polypropylene fiber was0.2%; the sample was cured for24h under the humidity of95%at the temperature between60℃and80℃, utoclaved curing at0.5MPa for8h and products could have the compressive strength of4.5MPa, dry density of763kg/m3. In preparation of perlite geopolymer materials, expanded perlite and glazed hollow beads should be dealed with water repellent, the better aggregate quality gradation was1：1, the appropriate mix content of the organic modifier was5%. The addition of Perlite in5%～10%, the compressive strength of pruducts was12～18MPa, density was915-1150kg/m3; When perlite mixed with other light aggregate, ceramsite content in40%, the compressive strength of pruducts was9.5MPa, the density was912kg/m3; Polystyrene particle volume content was30%, the compressive strength of pruducts was2.2MPa, the density was710kg/m3.Geopolymer materials was made, and explored the way how to make it lightweight, the material base was analyzed by FTIR, X-ray diffraction, SEM techniques, material product was amorphous state, and in which with a small amount of montmorillonite, quartz and feldspar crystal chip, chemical bond is ionic bond and covalent bond; There are a large number of gel phase and unreacted raw materials, light aggregate and unreacted raw materials were wrapped by gelling material, the three-dimensional network structure of the polymer was formed.