Experimental Study On Recovery And Utilization Of Waste Slurry From Mixing Plant

In the new era,the economy is turning into a stage of high-quality development,which promotes the standardization,economization and environmental protection of the commercial concrete industry.Production of commercial concrete station in the whole process will produce a large amount of waste pulp,waste pulp contains a small amount of cement hydration products and the residues admixture,Ca(OH)2 content is higher,the p H is as high as more than 12,if these waste slurry can not get reasonable recycling,waste resources and cause environmental pollution at the same time.In view of the above problems,this paper studies the influence of reuse of waste concrete slurry on the performance of concrete with different strength grades from the basic properties of waste concrete slurry.The influence of waste slurry on the properties of cement and cement mortar was studied,and the following conclusions were obtained: waste slurry had no influence on the stability of cement,and the water consumption of standard consistency of cement and the fluidity of net slurry were less affected by the aging time of waste slurry.The mixing of waste slurry with different aging time has an effect on the working performance,flexural strength and compressive strength of cement mortar.The effects of different solid content,aging time and mixing amount on the working performance,mechanical properties and durability of medium and low strength grade concrete(C30 and C50)were studied experimentally.The conclusion is as follows: the working performance of concrete mixed with waste slurry is different from that of concrete mixed with tap water.With the same aging time,the higher the solid content of waste slurry,the lower the initial slump and expansion of concrete.With the same solid content,the aging time of waste slurry has little influence on the performance of concrete.The strength of medium and low strength grade concrete is related to the solid content and mixing amount of waste slurry.In a certain range,with the increase of waste slurry concentration and content,the strength of concrete tends to increase,but when the amount of waste slurry is too large,the strength of concrete will decrease.The mixing of waste slurry improves the chloride ion permeability of concrete.With the increase of solid content and content of waste slurry,the anti-carbonization depth of concrete decreases gradually.Study waste pulp of Ⅰ type admixture(fly ash and slag powder)and type Ⅱadmixture(fly ash and silica fume)the influence of C80 concrete performance,adopting the test means of SEM and XRD analysis on the impact of waste slurry on concrete reason,get the following conclusion: the increase of dosage of waste pulp,concrete slump and the expansion degree gradually reduce;With the increase of waste pulp content,initial setting time and final setting time increased,the use of Ⅱ type admixture thanⅠtype of concrete admixture of concrete initial setting time and final setting time is long;7 dⅠtype mineral admixture of concrete compressive strength is lower than the benchmark concrete compressive strength,and gradually reduce,but the late compressive strength is growing rapidly.Ⅱ type of mineral admixtures 7d compressive strength of concrete increases gradually,and the late compressive strength was reduced after the first increase trend.The mixing of waste slurry helps to improve the chloride ion permeability of concrete.The comprehensive recycling and utilization of the green environmental protection mixing station waste pulp can meet the requirements of different strength grade concrete performance,save a lot of water resources and mineral resources,eliminate the pollution to the environment from the source,have good economic benefits,social benefits and environmental benefits,and meet the requirements of sustainable development.