The Research On Gypsum Modification Of Blast Furnace Flue Gas Desulphurization Building

In order to promote the application of flue gas desulphurization gypsum which belong to industrial solid waste in new materials of wall,some basic research and modified experiments were carried out.In the paper,the flue gas desulfurization gypsum is the fundamental material,and add single or complex organic additives and inorganic admixtu.In this paper,the basic research of flue gas desulfurization gypsum was carried out without adding any additive,which is aim at explore the basic hydration law and performance,and used as the contrast with the other experiments.In order to find out the best waterproof additive and dosage,the waterproofing property of flue gas desulfurization gypsum was modified by single organic waterproof additive,and the regularity of different kind of waterproof additive acting on flue gas desulfurization gypsum was tested.Studying the influence of inorganic materials such as ordinary portland cement,fly ash,xigeda soil,lime on the properties of desulphurized gypsum under the condition of single addition,then taking the orthogonal test to study the change of the properties of the cementitious system by complex mixed desulphurized gypsum,ordinary Portland cement,Xigeda soil,lime and desulphurized gypsum,ordinary Portland cement,fly ash,lime.By experiment the optimum modified admixture type and its dosage are obtained,and the optimum mix ratio after modification of desulphurized gypsum is determined.The main results of this thesis are as follows:The water-gypsum ratio has a significant effect on the performance of desulfurized gypsum after hydration.When the water-gypsum ratio is low,the strength of flexural strength,compressive strength,water absorption rate and water resistance coefficient of desulfurized gypsum are inversely proportional to the water-gypsum ratio,and the lower water-gypsum ratio is,the stronger the mechanical properties of desulphurized gypsum are.However,when water-gypsum ratio is low,the setting time is rapid,which is unfavorable to the construction operation.Self-made organic water-repellent agent A,polysiloxane powder water-proof powder,sodium methylsilicate water-repellent agent and silicone hydrophobic agent have remarkable waterproofing effect on desulfurization gypsum,with the lowest water absorption rate of less than 1%.But with the exception of self-made organic water-repellent agent A,others improveslightly to desulfurization gypsum on resisting flexural strength,compressiving strength and water resistance coefficient increase little.After desulphurization gypsum,ordinary portland cement,fly ash and lime are mixed,the optimum mix ratio is desulphurized gypsum:ordinary Portland cement:fly ash:lime:water1.0: 0.08:0.1:0.1:0.7.Under this matching ratio,the specimen of 28 d dry compressive strength reached 35.08 MPa,and wet compressive strength reached 14.82 MPa,and dry flexural strength reached 7.33 MPa,and wet flexural strength reached 4.23 MPa,but the maximum flexural strength softening coefficient reached 0.81,the maximum compressive softening coefficient reached 0.52,the absorption rate was 0.17.After the desulphurized gypsum,ordinary Portland cement,Xigeda soil,lime mixed,and the mixture ratio is desulphurized gypsum:ordinary Portland cement:Xigeda soil: lime:water1.0:0.10:0.20:0.20:0.50,the dry compressive strength of the specimen reached 30.91 MPa for28 days.When the mixture ratio is desulphurized gypsum: ordinary Portland cement:Xigeda soil:lime:water 1.0:0.20:0.15:0.05:0.45,the maximum dry flexural strength of 28 days reaches7.53 MPa.When the mixture ratio is desulphurized gypsum: ordinary Portland cement: Xigeda soil:lime:water 1.0:0.20:0.20:0.05:0.60,the maximum softening coefficient of flexural strength is 0.64.