Construction Waste Recycling Fine Aggregate And Fly Ash Improvement Study On Strength Test Of Guilin Red-clay

With the continuous development of the society,the process of urbanization and shantytown reconstruction has accelerated the rapid growth of construction waste production.Due to the complex composition and high cost of recycling,construction waste has not been treated well.At present,the main treatment method for construction waste is the landfill method,which not only causes pollution to the ecological environment but also encroaches on the land,and also causes waste of resources.Related research shows that construction waste can be recycled after screening and mechanical crushing.Red clay as a special soil,because of its high liquid limit and other characteristics,as a roadbed filler,there are a lot of problems,affect the strength of roadbed and its safety,can't be used directly as roadbed filler.This paper focuses on the construction waste recycling and the engineering characteristics of red clay.Through the addition of quicklime,fly ash and construction waste recycled fine aggregate,the red clay of Guilin is improved,the mechanical properties of the improved red clay are studied,and the reconstruction of construction waste is analyzed.The applicability of aggregates was determined and the optimal blending ratio was determined in order to provide a basis for the application of subgrade fillers and the recycling of construction waste in the Red Clay area.The main research results are as follows:(1)Adding recycled fine aggregate can effectively improve the liquid plastic limit of red clay and change the soil gradation.The recycled fine aggregate also acts as a skeleton of the soil in the red clay,enabling the rigidity of the soil to be enhanced,thereby increasing the strength of the soil.(2)The addition of quicklime in red clay can lead to a series of chemical reactions,among which ripening reaction and carbonation reaction are the most obvious.The chemical reaction products can improve the liquid plastic limit of red clay,and can also rapidly improve the physical and mechanical strength of soil..(3)Fly ash mainly reacts with pozzolanic reaction in red clay,but its reaction rate is slow,while the reaction speed is increased under alkaline conditions.In the initial stage of curing,the incorporation of fly ash affects the strength of the improved soil.There is no increase in the decline,but with the growth of the age of curing,the strength of the improved soil is slowly increasing.(4)When two or more of quicklime,fly ash,and reclaimed fine aggregate are incorporated into red clay,the physical strength of the modified soil is different depending on the blending ratio and the four curing periods.For c and ? values,the c and ? values of lime-improved red clay blended with quicklime increase linearly and play a leading role;for unconfined compressive strength,curing period is 30 d,quicklime,fly ash and recycled fine bone The optimum blending ratio of the material is 9:15:15,which is the highest strength.It is proved that the three kinds of additives can effectively increase the strength and water stability of red clay under the interaction of the three materials,and provide a theoretical basis for the improvement of the red clay subgrade.