Experimental Study On Permeable Concrete Based On Synthetic Aggregate Of Iron Tailing Powder

With the acceleration of China’s urbanization process and the comprehensive implementation of the rural revitalization strategy,the hardened pavement has increased greatly,and the research and application of the pervious concrete pavement in line with the requirements of green environmental protection are in the ascence.On the other hand,a large amount of aggregate needed for infrastructure construction is increasingly difficult to obtain,while a large amount of iron tailings occupy the land as industrial waste and have a significant impact on the environment and safety.In order to respond to the national call for sponge city construction and active use of tailings waste,this paper adopts the synthetic aggregate of iron tailing powder to replace part of natural coarse aggregate,develops and produces a new type of material permeable concrete through experiments,and analyzes and tests its engineering performance and economic rationality.It provides theoretical basis and data support for the application of new-type pervious concrete in practical engineering.The main research contents are as follows:(1)The recycled aggregate raw material test on the synthetic aggregate of iron tailing powder shows that the synthetic aggregate has the characteristics of smaller overall particle size,more concentrated gradation and higher porosity.Put forward synthetic aggregate mixed with natural coarse aggregate,improve the thinking of grading,the iron ore tail different iron ore tail of synthetic aggregate synthetic aggregate content mixed with natural stone formation aggregate mixture of apparent density,bulk density,porosity,such as performance indicators,and according to the determination of the test data calculation combined aggregate voids.(2)Based on orthogonal experimental design method,volume method for mix proportion design,according to the specification and reasonable selection of the water/cement ratio,dosage of water reducing agent and target porosity,iron ore tail and four factors,synthetic aggregate content corresponding to various factors,respectively set up three different levels,combined with the improved feeding and mixing process,to make 108 a new type of waterproof concrete specimen.(3)The mechanical and water permeability properties of the new permeable concrete were measured,and the 7d strength,28d strength,water permeability coefficient and porosity of the specimens were measured respectively.It is found that when the water-binder ratio is between 0.28 and 0.32,the 28d strength of the new type of permeable concrete is between 20 and 33MPa,and the permeability coefficient is between 1.8 and 6,both of which meet the performance requirements of pavement surface layer and base layer.In addition,the measured permeability coefficient of the new type of pervious concrete with the same porosity is higher than that of the ordinary pervious concrete studied by other scholars,and the measured permeability coefficient of the new type of pervious concrete with the sam e porosity is slightly higher than that of the ordinary pervious concrete studied by other scholars.(4)The results of multiple orthogonal tests were analyzed,and the optimal ratio under certain compressive strength and permeability coefficient was obtained.On the basis of satisfying the optimal ratio under certain compressive strength and permeability requirements,specimens were made to measure the flexural strength and carry out freeze-thaw cycle tests.The test results show that the flexural strength and freeze-thaw performance of the composite aggregate pervious concrete of iron tailing powder meet the requirements of pavement pervious concrete specification.(5)Based on the urban road pavement engineering,the cost comparison calculation and analysis of the ordinary concrete,the reference to the ordinary permeable concrete and the new type of permeable concrete under the two optimal ratios are carried out,and the water-saving benefits and ecological benefits of the new type of permeable concrete are analyzed.The analysis results show that the cost of permeable concrete is lower than that of ordinary permeable concrete,and the permeable concrete synthesized by iron tailing powder meets the requirements of relevant codes.Moreover,because it can effectively use industrial solid waste to "turn waste into treasure",it has a good application prospect and promotion value.