Experimental Study On Strength And Durability Of Engineering Slurry Solidified With Composite Slag

With the rapid development of China’s construction industry,the number of various engineering construction projects is increasing,and the application of engineering mud is becoming more and more extensive.At the same time,it is also faced with the problem of disposal of waste mud.If it is not treated effectively and timely,it will not only cause serious pollution to the environment,but also lead to a large number of waste resources.Therefore,it is urgent to find an efficient and cheap method to dispose of engineering waste mud.In this paper,slag and lime are used as curing materials,and water glass is added as an activator to prepare a new composite curing agent.The curing agent is used to solidify engineering mud,and different slag lime mass ratios(19:1,17:3,15:5,13:7,11:9)are studied The influence of different water glass content(1%,3%,5%,7%,9%)and different sand content(0%,20%,40%,60%,80%,100%)on the unconfined compressive strength of the solidified mud,the best proportion of the curing agent is obtained and the reasonable amount of sand is determined.From this,the solidified mud with the best proportion is prepared.Continue the freeze-thaw cycle and dry wet cycle tests under the erosion of clean water and sodium chloride solution with different concentrations(10g/L,20g/L,40g/L),The durability of solidified mud under chloride corrosion was studied.Finally,the change of internal microstructure of solidified mud was analyzed by SEM microscopic test,and the strength growth and damage mechanism were studied.The main conclusions are as follows:(1)Through the ratio test of solidified slurry,the unconfined compressive strength of the solidified slurry sample increases first and then decreases with the change of the mass ratio of slag to lime,the amount of sodium silicate and the sand content;With the increase of curing age,the strength of the sample increases and the growth rate slows down obviously.Finally,the optimal mass ratio of slag to lime is determined to be 17:3and the optimal content of sodium silicate is 5%,and the unconfined compressive strength is 4.175 Mpa and the sand content is 40%,taking into account various factors,the durability of the solidified slurry under chloride corrosion is tested.(2)The freeze-thaw cycle and dry wet cycle durability tests of the solidified mud under the corrosion of clean water and sodium chloride solution of different concentrations were carried out.The results showed that after freeze-thaw cycle and dry wet cycle,the surface of the sample was damaged to varying degrees,and the more cycles and the higher concentration of sodium chloride solution,the more serious the damage was;In the freeze-thaw and dry wet cycle tests,the mass,longitudinal wave velocity,unconfined compressive strength and deformation modulus of the sample decrease with the increase of the number of cycles;In the freeze-thaw cycle test,with the increase of chloride concentration,the mass change rate and longitudinal wave velocity of the sample increased,and the unconfined compressive strength and deformation modulus decreased;In the dry wet cycle test,with the increase of chloride concentration,the mass change rate of the sample also increases,and the longitudinal wave velocity,unconfined compressive strength and deformation modulus decrease.(3)According to the research results and scanning electron microscope microscopic test,it is analyzed that the main reason for the strength growth of the solidified mud is the formation of cement materials such as calcium silicate hydrate(C-S-H)and calcium aluminate hydrate(C-A-H),which can bond with each other and play a role in filling pores in the solidified mud,so as to increase the strength;The main reason for the strength decline of the sample after the durability test is that after many freeze-thaw cycles or dry wet cycles,the internal hydration products of the sample are reduced,the bonding force between soil particles is weakened,and the internal structure is loose,which ultimately leads to the strength decline.The higher the chloride concentration,the more serious the corrosion to the solidified mud,and the lower the strength.Figure [46] Table [6] Reference [75]...