Research On Engineering Properties Of New Liquid Fly Ash

The experimental study and practical application of liquid fly ash,a lightweight backfilling material,are aimed at solving the problems of bridge head jumping,abutment instability and uneven settlement between the old and new roadbed in embankment filling during the roadbed backfilling and road expansion.The actual results show that liquid fly ash has the advantages of small dead weight,no need to vibrate,convenient construction and low price,which can effectively improve the stability of roadbed.In order to improve the performance of roadbed backfill material liquid fly ash and make it more in line with the needs of actual engineering application,this paper uses slaked lime to improve liquid fly ash to obtain a new lightweight flow backfill material,and carries out the following research and analysis:In this paper,according to the best mixing ratio obtained from the laboratory test of liquid fly ash and actual engineering application,and referring to the relevant specifications of the stabilized materials of slaked lime and cement,the dosage range of slaked lime in new liquid fly ash and the initial mixing ratio of new liquid fly ash that meets the requirements of actual engineering filling were determined.Based on the analysis of the relationship between the admixture and fluidity,strength and wave velocity in the newly mixed liquid fly ash through the test system,the optimal water consumption for the material to meet the requirements of the material fluidity in actual engineering construction was obtained.Rough set theory is used to objectively analyze and evaluate the factors that affect consistency and strength.The density,setting time,shrinkage deformation and water stability tests were carried out on the mixture ratio of newly mixed liquid fly ash whose strength met the requirements.The mixture ratio of newly mixed liquid fly ash was further optimized to determine that the material had better stability performance.Through the above experiments and analysis,the following conclusions can be drawn:(1)when the water consumption in newly mixed liquid fly ash is about 62%,the fluidity of mixture is the best;(2)In the newly mixed liquid fly ash,when the total amount of cement and slaked lime is about 14%,the mixture is more compact and uniform inside,with the best strength;There is a good correlation between wave velocity and strength,as well as between the strength of the cylinder specimen and the cube specimen.(3)According to the rough set theory analysis,the conclusion is drawn that the weight order of influencing factors affecting the consistency value of new liquid fly ash is:water dosage>cement dosage>lime dosage;The weight order of influencing factors affecting the 7d strength of newly mixed liquid fly ash is:cement dosage>lime dosage;The weight order of influencing factors affecting the 28 d strength of newly mixed liquid fly ash is:cement dosage>lime dosage>fly ash dosage;it is more economical to choose fresh liquid fly ash with less lime than cement.(4)In the mixture ratio of newly mixed liquid fly ash,cement dosage:lime dosage:fly ash dosage of 6:4:90 is lighter,high strength,dry shrinkage,strong water stability,more suitable for roadbed backfilling engineering.