| Engineering construction waste mud is a kind of suspension composed of water,bentonite particles,cohesive soil particles and admixtures.Its natural sedimentation and direct dewatering effect are poor,and improper treatment may cause environmental pollution.The chemical curing method can effectively improve the engineering characteristics of the waste mud.The curing agent is the key factor affecting the performance of the solidified mud.Therefore,the development of a high-efficiency curing agent has high engineering application value.In this paper,the development and test of composite curing agent is carried out for the construction of waste mud.The main work and achievements are as follows:(1)A single-mixing test was carried out,in which cement,quicklime,water glass,fly ash and raw gypsum were separately used as solidified materials in the engineering construction waste mud to test the strength of the solidified mud for 7d,14 d,28d and 60 d ages.The moisture content and pH value show that the strength and pH value of the solidified mud increase with the increase of the solidified material content;the moisture content of the solidified mud decreases with the increase of the solidified material content;the cement has the best curing effect;the curing age The longer the period,the higher the strength of the solidified mud;the cement and water glass solidified mud strength shows early growth and slower in the early stage,and the strength of the quicklime,fly ash and raw gypsum solidified mud shows slow growth in the early stage and fast in the later stage.(2)Conducted an orthogonal test to optimize the curing agent formulation consisting of cement,quicklime,water glass,fly ash and raw gypsum,and test the 7d and 28 d age strength of the solidified mud,and analyze the test results.The results show that the optimal ratio is 14% cement,7% lime,5% water glass,7% fly ash,and 3% raw gypsum.The curing agent formula is named F-12);The degree of influence of the solidified material on the 7d age strength of the solidified slurry is: cement>water glass>fly ash>lime>green gypsum;the degree of influence of the solidified material on the 28 d age strength of the solidified slurry is: cement>water glass > Quicklime > Fly ash > Raw gypsum.(3)On the basis of the curing agent F-12,sodium dodecylbenzenesulfonate was added to test the strength of the solidified mud for 7 days.The results showed that the strength of the solidified mud was mixed with sodium dodecylbenzenesulfonate.For the lifting effect,the optimum dosage is 1%(the curing agent formulation is named G-12).(4)The strength comparison test of self-made curing agents F-12,G-12 and several other curing agents was carried out.The results showed that the curing effect of self-made curing agents F-12 and G-12 was more in improving the strength of solidified mud.good.(5)The compaction test and CBR test of the solidified slurry with the curing age of 7d in the single-mixing test showed that the optimum moisture content and maximum dry density of the solidified mud are related to the type and amount of the solidified material;The optimum moisture content and maximum dry density of the solidified mud increased and decreased,respectively.Under the same dosage,the optimal moisture content of the quicklime solidified mud was the largest,and the maximum dry density of the fly ash solidified mud.The minimum moisture content of the solidified mud is 24%~30%,and the maximum dry density is 1.60g/cm3~1.83g/cm3;the CBR value of the solidified mud increases with the increase of the solidified material content,and the cement is solidified.The mud bearing ratio is the most obvious.(6)The self-made curing agent F-12 is used to solidify the waste mud,and the solidified mud is subjected to moisture content test,compaction test and CBR test.The results show that the solidified mud with the curing age of 24 d can be filled and crushed.The degree of compaction and CBR can meet the requirements for the use of packing for roadbeds and embankments. |
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