Application Of Reclaimed Concrete Of Construction Waste Iron- Containing Tailings In Foundation Treatment

Since the reform and opening up,China's urbanization is accelerating rapidly.The concrete,as an alternative building material,its annual consumption is very large.This not only results in the consumption of a large amount of natural ore but also the birth of tens of millions of construction waste.These construction wastes take up a large amount of land and cause serious pollution to the surrounding environment.At the same time,with the rapid development of China's economy,a large number of mines are overloaded,resulting in rapid consumption of mineral resources,among which iron tailings have become the waste with the largest output and the lowest comprehensive consumption rate in China.In order to solve the above problems,iron tailings recycled concrete technology comes into being which is applied in foundation treatment and other projects In this way,not only construction waste and iron tailings can be developed and utilized but also natural sand and sand resources can be alleviated,which has great research and application value.This article mainly studies the abandoned concrete left by demolition and iron tailings left by mineral processing in zhangjiakou area.At last,a large direct shear contact surface test is carried out to study the pile-soil contact surface,and to provide theoretical basis for practical engineering.Firstly,the basic physical properties of aggregate are tested in the laboratory and the mixing ratio suitable for iron tailings recycled concrete is put forward through the test results.On this basis,the compressive strength test of the test block is carried out,and the theoretical strength formula suitable for regenerated concrete of iron tailings in the foundation treatment project is obtained through analyzing the design results of orthogonal combination test of quadratic regression.According to the main line of the paper,the main research can be divided into the following points:(1)The laboratory physical property test of soil,iron tailings and recycled aggregate mainly includes screening test,Compaction test,water content test,water absorption rate,crushing index and other tests.The soil and aggregate were classified according to the test results,and the concrete mix design was prepared according to the specifications and the monitoring data in the actual project.(2)On the basis of the above tests,the unit water consumption suitable for the preparation of recycled concrete from iron tailings is put forward.In the first step,the influence of the iron tailings content,water-cement ratio and additional water amount on the compressive strength of iron tailings recycled concrete is considered.Then the quadratic regression orthogonal test design is carried out to determine the theoretical formula that meets the requirements of foundation treatment engineering.(3)The optimal concrete preparation scheme affecting the test results in the above(2)was prepared into specimens,the contact surface shear test was conducted with a large direct shear apparatus to study the shear characteristics of the contact surface,so as to further investigate the possibility of applying iron tailings recycled concrete in foundation treatment projects.