Study On The Preparation Of High-performance Sleeve Grouting Material And Its Application In Low Temperature Environment

Assembly building is the trend of the future development of the construction industry,and the performance of the sleeve grouting material is very important for the safety and stability of the whole assembly building.At present,there are many gaps between domestic and foreign grouting materials.In the application process of practical projects,there are still problems such as insufficient strength,poor workability,insufficient expansion rate and poor performance in low temperature environment.Therefore,the development of high-performance sleeve grouting materials and their application in low temperature environment are of great significance for the development and promotion of prefabricated buildings.In this project,the ternary composite cementation system of ordinary portland cement,sulphoaluminate cement and dihydrate gypsum is adopted,graded quartz sand is selected as fine aggregate,silica fume and fly ash are selected as mineral admixture,retarder is used to solve the problems of short setting time and poor workability of sleeve grouting material,defoamer is used to eliminate harmful bubbles in slurry,and orthogonal design test is carried out The optimal mix of water binder ratio,water reducing agent and thickener is selected,and the optimal formulation of sleeve grouting material is obtained.The one-way tensile test of sleeve grouting joint is carried out to verify the practical application performance of sleeve grouting material.In addition,on the basis of determining the optimal ratio of sleeve grouting materials,the influence of environmental temperature,mixing water temperature,pre curing time and different early strength antifreeze components on sleeve grouting materials in low temperature environment is studied,and two kinds of sleeve grouting materials winter construction temperature maintaining measures are put forward in combination with the research results.The results show that:(1)When the proportion of ordinary portland cement and sulphoaluminate cement is 7:3,the mechanical properties,flow performance and setting time of sleeve grouting material are excellent,and the early strength is high.Compared with anhydrous gypsum and ?-hemihydrate gypsum,dihydrate gypsum has better mechanical and working properties,and its expansion performance is guaranteed.(2)The control variable method test shows that the performance of sleeve grouting material is the best when the content of retarder is 0.25%,defoamer is 0.2%,silica fume is 2% and fly ash is 4%,and the ratio of binder to sand is 0.9.(3)the best combination of water binder ratio,water reducer and thickener was determined by orthogonal design.According to the comprehensive results,the optimal values are 0.24% water binder ratio,0.8% water reducer and 0.02% thickener.The results of range analysis orthogonal test show that the water binder ratio has the greatest influence on 28 d compressive strength and 30 min fluidity;the water reducer has the greatest influence on 1D and 3D compressive strength;the thickener has the greatest influence on the initial fluidity.At the same time,one-way tensile test was carried out on the grouting sleeve joint of the final grouting material,and the test results showed that the steel bars were broken,indicating that the performance of the grouting material prepared in this test is excellent,and it can be used as the sleeve grouting material in the assembly building.(4)The compressive strength of the sleeve grouting material decreases with the decrease of the ambient temperature.When the ambient temperature is 5 ?,the compressive strength of the grouting material can no longer meet the requirements of the specification.Increasing the mixing water temperature has little impact on the compressive strength of the sleeve grouting material,and will sharply reduce the 30 min fluidity of the grouting material.At 0 ?,the sleeve grouting material needs to be cured at 10 ? 20 ? When the content of lithium sulfate is 0.2%,the low temperature performance of sleeve grouting material is the best.(5)Two kinds of heat preservation measures,the electric blanket plus XPS heat preservation board and the electric tracing tape wound on the outer wall of the sleeve,can heat the grouting slurry in the sleeve,and maintain the internal temperature at 10 ? 20 ?,which provides a favorable temperature environment for the hydration process of the grouting material.Finally,the feasibility of the two insulation measures is verified by the uniaxial tensile test of the sleeve grouting joint.