Experimental Study On Basic Mechanical Properties And Durability Of Iron Tailings Sand Geopolymer

Geopolymer is a new type of green building material,characterized by wide sources of raw materials,high early strength,and good durability,and has advantages in solid waste resource utilization.In this study,to realize the resource utilization of iron tailings sand,iron tailings sand geopolymer with good mechanical properties was prepared at room temperature with slag as the main raw material and iron tailings sand as admixture.Through three factors and three levels orthogonal experiment to optimize the mix proportion,the optimal strength mix proportion of iron tailings sand geopolymer was obtained,and on this basis,the main factors and laws affecting the basic mechanical properties were studied through the analysis of mix proportion.The durability of the geopolymer was studied through freeze-thaw,aging and chemical erosion tests,which provided a reference for its development and application.The main research contents and conclusions of this paper are as follows:(1)Study on optimization of preparation process and mix proportion.The preparation process and basic mix proportion of the iron tailings sand geopolymer were determined through the trial test.Based on the three factors and three levels orthogonal test with fly ash content,water-binder ratio and iron tailings sand content as the influencing factors,the influence order of each factor on the strength of the iron tailings sand geopolymer was obtained,and the optimal value of the three factors was determined.The optimal mix proportion of iron tailings sand geopolymer is iron tailings content is 20%,fly ash content is 10%,slag content is 70%,waterbinder ratio is 0.3,and the mechanical properties are the best.The compressive strength of28 days under room temperature standard curing reaches 70.10 MPa,and the strength reaches the P.O 42.5 R cement strength standard.(2)Study on the basic mechanical properties of iron tailings sand geopolymer.The cube compressive strength and flexural strength of the iron tailings sand geopolymer were tested through experiments,and the influence of fly ash content,iron tailings sand content and waterbinder ratio on the basic mechanical properties of the iron tailings sand geopolymer was studied.Appropriate dosage of iron tailings sand and water-binder ratio can improve the basic mechanical properties of geopolymer.The optimal dosage of iron tailings sand is 20%,the optimal water-binder ratio is 0.3,and the strength of geopolymer decrease with the increase of fly ash content when the fly ash content is more than 10%.(3)Study on durability of iron tailings sand geopolymer.Based on frost resistance,ultraviolet aging resistance and chemical erosion resistance tests,the durability of iron tailings sand geopolymer was studied.The test results show that the frost resistance,hydrochloric acid resistance and sulfate resistance of iron tailings sand geopolymer are better than those of ordinary Portland cement.The strength attenuation performance of iron tailings sand geopolymer against ultraviolet aging is better than that of ordinary Portland cement,but the mass loss is worse than that of the latter.The drying shrinkage of iron tailings sand geopolymer is greater than that of ordinary Portland cement.The drying shrinkage of the geopolymer can be reduced by increasing the amount of fly ash and iron tailings sand and reducing the water-binder ratio.