Mechanism Of Multi-source Solid Waste Co-curing Of Red Sandstone Residue And Its Road Performance

In China,red sandstone is widely distributed,and a large amount of red sandstone residue will be produced during the construction process,which has the characteristics of high water content,low strength,large compression and deformation,and very poor water stability.On the other hand,China still faces serious challenges in the resource utilization of industrial solid waste,such as high treatment cost,insufficient utilization and low added value of products.In order to solve the above problems,a solution of "treating waste with waste and turning waste into treasure" is proposed.Using the principle of synergistic and complementary utilization of multiple industrial solid wastes,an economical and efficient multi-source solid waste compound curing agent is developed to cure and improve red sandstone residue to make it a good filler material.The mechanism of curing and improving red sandstone residue,as well as the mechanical properties and durability of the road before and after curing and improving were studied.The main research contents and results are as follows:(1)The basic physical property indexes of red sandstone residue were tested to provide data support for subsequent curing treatment.A series of improvement measures for red sandstone residue were proposed,and the influence law of each curing raw material on red sandstone residue was analyzed by single-mixing test to find the suitable mixing interval;the interaction between curing materials was studied by orthogonal test.Finally,the best ratio of multi-source solid waste compound curing agent was determined by considering multiple factors: 4% quicklime,4% fly ash,8% calcined coal gangue powder,7% cinder powder,and the developed multi-source solid waste compound curing agent is characterized by low cost,wide application range and good curing effect.(2)Through a series of microscopic experimental technical means,the changes of material composition,pore structure and skeletal structure in red sandstone residue soil were studied to reveal the mechanism of action of multi-source solid waste composite curing agent for curing and improving red sandstone residue soil.After the synergistic and complementary utilization of multiple curing raw materials,the interaction between multi-source solid waste compound curing agent,water and clay particles in red sandstone residue soil,a series of physical and chemical changes occurred,resulting in new substances,and the rearrangement and combination between soil particles and cementing substances,resulting in a new structure,which finally realized the curing and improvement of red sandstone residue soil.(3)The strength,deformation and damage resistance of cured red sandstone residue were tested by unconfined compressive strength test,direct shear test,compression test and bearing ratio test(CBR)to provide solid data reference for the road performance of cured red sandstone residue.The test results show that the strength,deformation resistance and damage resistance of cured red sandstone residue are greatly improved compared with that of red sandstone residue and can meet the requirements of general road foundation projects.(4)The water stability test,dry and wet cycle test,long-term immersion strength test and permeability test of red sandstone residue soil before and after curing were carried out to compare and analyze its water stability,dry and wet alternation,long-term immersion,impermeability and other properties.The test results show that: the uncured red sandstone residue has poor water stability performance,which is not conducive to the long-term operation of the roadbed project,and the durability of the cured red sandstone residue is greatly improved to meet the long-term stability requirements of the roadbed project.