Research On The Modification Of The Industrial Waste FGD Gypsum And Application In Construction Engineering

Flue Gas Desulphurization Gypsum,also known as FGD gypsum,is a kind of industrial byproducts resulting from the process of Flue gas desulphurization and purification,which is generated by combustion of sulfur-containing fuels.Calcium sulfate dehydrate?CaSO₄·2H₂O?is the main component of FGD gypsum,which is yellow or gray in color and fine in grain.With the rapid development of economy,FGD gypsum has become a major source of solid waste.Large amount of FGD gypsum are produced and abandoned each year,which not only consume a great deal of land resources,but also cause serious pollution of the ecological environment.In accordance with the strategy of Scientific Outlook on Development and Resource Utlization,the processing and utilization of FGD gypsum is not only an effective way to promote national environmental protection and recycling economy,but also a stimulus to reduce the exploitation of gypsum mine.FGD gypsum was taken as the research object in the thesis.In terms of performance,it was studied by modification of FGD gypsum by adding cement,leading to an improvement of the mechanical property and the growth mechanism of the strength was explored by micro-experiment.Experiments on the linear expansion was conducted to explore the expansion and shrinkage of gypsum with the change of temperature and humidity,and it was found that the temperature and humidity influence gypsum specimen by changing the structure of calcium sulfate dihydrate and ettringite crystals.As for the application of FGD gypsum,rapid plasterboard filled with concrete was studied.By exploring the change tendency of lateral pressure on formwork in the process of concrete pouring based on the burst and slurry leakage of the template,it was found that the distribution of the lateral pressure follows the law of fluid statics;To investigate the mechanism of cracks appearing on the surface of gypsum wall in engineering,the finite element calculation model based on ABAQUS was established,to simulate the effect of adhesive between gypsum board and concrete on the expansion,and the expansion capacity of gypsum board under different constraint conditions was calculated.It was proposed to set the expansion joint based on the simulation results and has been verified by field experiments,which have a guiding significance to the practical engineering projects.