Preparation Of Foamed Geopolymer And Study On Thermal Conductivity And Fire Resistance

This article explores the setting time of geopolymers by adding three different blowing agents?Al powder,H₂O₂ and plant blowing agent?to the geopolymer to change the composition and preparation process of the geopolymer.After obtaining a formulation with a high degree of co mpatibility with the blowing agent,the preparation of the porous geopolymer was carried out,and the mechanical properties thereof were studied.A set of test pieces with good performance was selected for observation of the internal pore structure and measurement of thermal conductivity.Finally,the prepared geopolymers were tested for fire resistance according to the specifications,and the appearance and strength changes were recorded.The samples subjected to high temperature treatment were sampled for XRD microscopic measurement to find the root cause of the macroscopic properties of the geopolymer.?1?The main influencing factors of the coagulation time of the geopolymer are the temperature of the activator,the alkalinity of the activator,the amount of water,and the externally mixed powder.The temperature of the activator and the alkalinity have a great influence on the setting time.The test can control the initial setting time and final setting time of the geopolymer to 10min³25min and 25min⁴25min respectively,and the 7d intensity is 15.6M P²4.3M Pa.?2?A foaming geopolymer havin g an Al powder content ranging from 0.00%to0.09%and a H₂O₂ content ranging from 0.00%to 0.70%is prepared.With the increasing amount of foaming agent,the flexural strength and compressive strength of geological polymer specimens gradually decreased.The 28d flexural strength and compressive strength of geopolymers without foaming agent were respectively The 28d flexural strength and compressive strength of 3.5MPa and 31.7M Pa,0.09%Al powdered geopolymers were 1.9M Pa and 19.9M Pa,respectively.The 28d flexural strength and compressive strength of 0.7%H₂O₂ geopolymer were respectively It is 1.8M Pa and 10.4 M Pa.?3?The plant foaming agent is used in the manner of 30-fold dilution and 20-fold dilution of the stock solution.After testing,it is found t hat the quality of the geopolymer is reduced,the average mass can be reduced by 14.25%,and the average intensity can be reduced by 10.73%.Compared with the chemical foaming method,it has a poor effect on the quality reduction of geopolymers.?4?Through the observation and statistics of the internal pore structure of various porous geopolymers,the pore structure inside the geopolymer can be roughly classified into four types according to the shape and size:50?m-500?m aperture circular macro hole,500?m-800?m aperture circular macro hole,1000?m long diameter elliptical macro hole and giant pore structure larger than 1000?m diameter.Among the porous geopolymers foamed with Al powder and H₂O₂,the above pore structure can be clearly observed,and the above pore structure cannot be clearly observed by the plant foaming agent geopolymer.?5?The thermal conductivity is the lowest when 0.09%Al powder is added,the average thermal conductivity is 0.4979W/m/K,and the lowest is 0.099 W/m/K when the H2O2 content is 0.6%,and the plant foaming agent group is reduced less.At t he lowest,it reaches 0.978 W/m/K.?6?When the temperature reaches 800°C,the rate of transformation of the amorphous gel inside the crystal to the crystal will increase,and the characteristic peak with large diffraction intensity will appear everywhere in the image.The characteristic peaks of Fe₂O₃,Al₂O₃ and CaCO₃.