Experimental Study On Prevention And Cure Of Bumping At Bridge Head With Foam Concrete Mixed With Municipal Solid Waste Combustor Ash

The bumping at bridge head is a common problem in Bridge,which refers to the wheel vibration caused by the differential settlement between the abutment structure and the abutment embankment when the vehicle passes through the junction of road and bridge.After a large number of research and analysis of the causes and principles of the bumping at bridge head,the domestic scholars have proposed reasonable and effective treatment and prevention measures,and foam concrete used as backfill material is a convenient and effective method.At present,the phenomenon of "garbage besieged city" is becoming increasingly serious.Although incineration treatment has a significant effect in large and medium cities,landfill sites needed are still too large.The resource reuse of municipal solid waste combustor ash has become an urgent problem.So this paper intends to make foam concrete mixed with municipal solid waste combustor ash to meet requirements for replacing materials in codes and professional standards to prevent and control bumping at bridge head.To this end,the following experiments were carried out.(1)The physical and engineering characteristics of the Municipal solid waste combustor ash have been researched.The research on municipal solid waste combustor ash from Dongxihu District of Wuhan tested grain composition,apparent density and water content,compaction characteristics and load ratio of the municipal solid waste combustor ash.Test results prove that municipal solid waste combustor ash is lighter than the usual gravel,and it has good compaction characteristics and larger load ratio,which is suitable as aggregate of foam concrete.(2)The influence of various factors on the performance of foam concrete has been summarized,and the optimum mix ratio of foam concrete has been determined.By analyzing the principle of mix design of foam concrete,this paper developed detailed laboratory experiments and tested the compressive strength,dry density and water absorption of municipal solid waste combustor ash.On this basis,the influence of various factors on the performance of foam concrete has been summarized,and the optimum mixratio of foam concrete has been determined.(3)The pavement performance of foam concrete with the optimum mix ratio has been tested.According to "The application technical specification of highway engineering foam concrete"(DB33/T 996-2015),this paper tested that fluidity and unconfined compressive strength of foam concrete with the optimum mix ratio,and the results prove that foam concrete with the optimum mix ratio has good fluidity and can also meet the requirements of dry density and compressive strength at once to prevent and control bumping at bridge head.(4)The leaching content of heavy metals of municipal solid waste combustor ash and foam concrete mixed with municipal solid waste combustor ash has been tested.The paper tested the leaching content of heavy metals of municipal solid waste combustor ash and foam concrete mixed with municipal solid waste combustor ash,the results show that the leaching content of heavy metals of municipal solid waste combustor ash remain in a relatively low level and cement has a good solidification effect on heavy metals,so the leaching content of heavy metals of foam concrete mixed with municipal solid waste combustor ash meet environmental requirements.