Experimental Study On The Performance Of Dry Mixed Mortar With Sludge Sinter From Municipal Sewage Treatment Plant

The acceleration of urbanization and the explosion of population have led to an increase in sludge.The issue of sludge disposal has aroused people's attention,of which sludge construction materialization is a relatively good disposal method for sludge disposal.In this project,the incineration ash of sludge was sieved into 0-5mm fine aggregate according to the particle size of ordinary sand,and 100% replaced the fine aggregate in ordinary mortar to make dry mixed mortar.First,the feasibility of sludge sintered material as dry aggregate mortar fine aggregate was tested for chemical composition,leaching amount of heavy metals,pore structure(using MIP method),physical performance indicators,and radioactivity.The results met the requirements of current national standards.Then,referring to the design strength of the ordinary mortar,three strength grades of M5,M7.5,and M10 are selected;in order to improve the performance of the mortar,fly ash,granulated blast furnace slag powder,and limestone powder are used in a single blending method,and the blending amount is 10%,20%,30%,the mortar(control group)made of machine-made sand is set as the control group.And check the working performance,compressive strength,tensile bond strength,dry shrinkage rate,dry density,thermal conductivity of mortar.The results are as follows:(1)Working performance: after adding fly ash,mineral powder and limestone powder,it is found that when the content of fly ash is 30%,the improvement effect on mortar is more obvious,but it is still less than the work of mechanical mortar under the same water-binder ratio Performance and increasing the water-to-binder ratio can also improve the performance of the sludge sinter mortar(test group).(2)Compressive strength: The compressive strength of the ore powder on the mortar of the test group is more obvious,with a higher strength value of 3.96 MPa,and the water-binder ratio has little effect on the mortar of the test group.Under the same water-to-binder ratio,the compressive strength of the mortar of the test group is less than that of the control mortar.(3)Tensile bond strength: The mineral powder has greatly improved the tensile bond strength.When its content is 20%,the tensile bond strength is 0.203MPa;when the water-binder ratio is increased,it affects the test group mortar It is more obvious and the strength decreases more;the tensile bond strength of the mortar in the test group is lower than that in the control group.(4)Dry density and thermal conductivity: when the limestone powder content is 30%,the dry density and thermal conductivity of the mortar are smaller 337kg/m3 and 0.268W/mK,respectively;the dry density and thermal conductivity of the mortar in the test group follow the water glue The ratio increases and decreases.However,when the water-binder ratio of the test group is 0.68,the dry density and thermal conductivity are greater than those of the other two groups;under the same water-binder ratio,the dry density and thermal conductivity of the test group are less than the control Group mortar.The trends of compressive strength,dry density and thermal conductivity are the same.(5)Drying shrinkage rate: when the percentage of fly ash is 30%,it is more effective to inhibit the drying shrinkage rate of the mortar;as the water-binder ratio increases,the drying shrinkage of the mortar gradually increases;In this case,the drying shrinkage of the mortar in the test group was slightly smaller than that in the control group.