The Research On Alkali-activated Preparation And Performance Of Fly Ash Geopolymer

Geopolymer material is a kind of green inorganic gellled material,with three-dimensional network structure,which is activacted silicon aluminum material by alkali.There are many excellent properties,such as early rapid hardening strength and high temperature resistant and acid and alkali resistant.And abundant raw material,for example metakaolin,fly ash,slag and other industrial solid waste,and low cost,low energy consumption,low pollution,simple in preparation process,and a kind of new environmental protection material.Therefore,geopolymer material has a good application prospect in building materials and daily life and factory production.In this paper,fly ash geopolymer materials were preparated with fly ash excitated by alkali,which to select the optimal preparation methods.The main results were as follows:The optimum technological parameters of optimal performance for fly ash geopolymer are as follows:when mix 50g/35% compound alkali with the modulus is 0.8,then curing for 8h under 80?.Then under normal temperature wet curing for a period of time.The compressive strength of the sample of 5d is P1=70.9MPa,7d is P2=71.3MPa,28 d is P=75.81 MPa.Thus the early polymerization of fly ash geopolymer have been finished in the5 d.The results of high temperature resistant of fly ash geopolymer materials show that with the increase of the calcination temperature,the mass loss rate is increased.In front of the calcination temperature is 400,the compressive strength of the specimen increases with the increase of calcination temperature.however,the calcination temperature higher than 400,the compressive strength of the specimen is worse instead.When the calcination temperature is800,the mass loss rate and the compressive strength of samples have been basically unchanged.The test of fly ash geopolymer of acid and alkali resistance shows that in the H2SO4 solution,the mass loss rate increases with increasing concentration of acid solution,but the compressive strength declines.However in NaOH solution,when in the low concentration,the quality and the compressive strength of the sample increase with increasing concentration of alkali;but in the high concentration,the mass loss rate increases with increasing concentration and the compressive strength decline.In a word,the experiment show that fly ash geopolymer materials is better than ordinary silicate materials in high temperature resistant and acid and alkali resistant.The experiment examines the influence of admixture,metakaolin-fly ash geopolymer and sand-fly ash geopolymer were prepared with the respectively optimal dosage is 20%?15%in the optimal prepared condition.And samples tested by high temperature resistant ?acid and alkali resistant.The result shows that metakaolin-fly ash geopolymer better than fly ash geopolymer,and fly ash geopolymer better than sand-fly ash geopolymer.