Normal Temperature Type Sleeve Grouting Material Mixed With Mineral Admixture Research On Optimization Of Mixture Ratio

Prefabricated concrete buildings are the inevitable trend of my country’s current construction industrialization.Reinforced sleeve grouting connection is the main method of node connection in prefabricated concrete structures.Therefore,the performance of the sleeve grouting material plays a vital role in the quality and safety of the entire prefabricated building.The grouting material used in actual engineering has problems such as insufficient strength,poor fluidity,which need to be solved urgently.The use of mineral admixtures can not only effectively improve the performance,but also reduce the cement consumption,saving resources,reducing environmental pollution and reducing costs.At present,there are too many types of mineral admixtures in the grouting materials sold on the market and the performance improvement is not obvious.Therefore,this topic has launched a research on the influence of mineral admixtures on the performance of normal temperature type sleeve grouting material and optimized the design of the mixture ratio.Aim to study and formulate a high-performance normal temperature type sleeve grouting material.In this paper,the ternary composite cementing system of ordinary portland cement,sulfoaluminate cement and dihydrate gypsum was mixed with graded quartz sand and additional components.Firstly,the five mineral admixtures of fly ash,slag powder,phosphorous slag powder,metakaolin and steel slag were doped separately,three admixtures were selected,and two percentages of each mineral admixture were selected and then orthogonal test was carried out,and through the objective weight assignment and grey relation degree method to accurately analyzed the results of the orthogonal test and selected the best mixture ratio.In addition,estimating the cost of the final selected mixture ratio grouting material,and comparing which with the blank group and the better mixture ratio grouting material selected by the orthogonal test group.And finally,through the unidirectional tensile test on the full grouting sleeve joint,to verify the actual feasibility of the final selection of grouting material.Through experimental research,the main conclusions obtained are as follows:(1)The five mineral admixtures of fly ash,slag powder,phosphorous slag powder,metakaolin and steel slag were tested by the controlled variable method.The analysis data and comparative performance could be obtained:4%,6%fly ash,15%,20%slag powder,and 1%,3%metakaolin were doped separately,the fluidity and compressive strength of the sleeve grouting material are relatively good;the performance of phosphorous slag powder and steel slag The performance is relatively poor,so no further orthogonal test research on it.(2)Using the orthogonal design method to select the orthogonal table L9(3~3)for the six selected dosages,make nine sets of related experimental studies,and perform the objective weight assignment and grey relation degree method analysis on the orthogonal test results.Finally,the test group of the best mineral admixture ratio is:K20F6P3;the cost of the grouting materials was estimated based on the current market price of the raw materials selected in this experiment,and it is found that the final optimized mixture ratio is more cost-effective.(3)Based on the optimal mixture ratio of the sleeve grouting material obtained by the research,a unidirectional tensile test of the sleeve grouting joint was carried out.The test result was that the steel bars were all broken,indicating that the performance of the normal temperature type sleeve grouting material prepared in this experiment is better.And it can be used in actual prefabricated buildings.