Preparation And Construction Technology Of Alkali-Activated Manufactured Sand Powder-Slag Multiple Composite Grouting Material

During the production process of manufactured sand powder,it is inevitable to produce a large amount of stone powder.Due to factors such as stone powder activity and water demand,the addition of stone powder into concrete is detrimental to its physical and mechanical properties.Therefore,relevant regulations strictly limit the content of stone powder in manufactured sand,resulting in a large amount of stone powder being stacked,not only causing resource waste,occupying a large amount of space,but also causing environmental pollution,How to efficiently utilize it as a resource has become a hot topic of concern.Alkali activated materials are a type of building materials mainly composed of waste residue.At the same time,due to the goal of"carbon neutrality"and the utilization status of industrial waste residue,the application of green building materials will gradually become the mainstream.Alkali activated materials have the characteristic of high early strength,which is in line with the application requirements of grouting materials.In the research of alkali activated materials,the main focus in the past was on the activation of slag and fly ash,with relatively little exploration of waste residues such as stone powder and rice husk ash.Therefore,the preparation of multiple composite grouting materials from waste residues such as manufactured sand powder and slag promotes the reduction of waste residues and the development of carbon emissions reduction,meeting the needs of engineering applications.In this thesis,the composite grouting material is prepared by using manufactured sand powder,slag,fly ash and cement as the main raw materials,and its working performance,mechanical properties and volume stability are studied.The diffusion of slurry in soil and its influence on soil stability during grouting are analyzed.Finally,the construction technology of composite grouting material is put forward.The main research contents and conclusions are as follows:（1）Optimize the best mix ratio parameters of composite grouting materialsThe modulus of water glass,alkali content,water-binder ratio and stone powder content were selected as the key factors,and the fluidity,setting time,compressive strength and drying shrinkage were used as the test indexes.The analysis shows that by adjusting the modulus of water glass and alkali content,the fluidity is up to 401 mm,the setting time is up to 505 min,and the 1d compressive strength is up to 18.7 MPa.Although increasing the water-binder ratio can significantly improve the fluidity,it will significantly prolong the setting time and reduce the strength,which should not exceed0.6.The content of stone powder should not exceed 10%;the expansion agent can effectively reduce the drying shrinkage,and the order of shrinkage reduction effect is:Ca O expansion agent>Mg O expansion agent>SC expansion agent.The optimum dosage is 8%（Ca O expansion agent）,and the 28d shrinkage is reduced to 432×10^-6.（2）The influence of different grouting parameters on slurry diffusion and soil stability is explored.The numerical analysis of soil grouting was carried out by FLAC3D software.The extension law of slurry diffusion range under different grouting pressure（0.2～0.8MPa）and time（0～30min）was compared.The indoor test of grouting diffusion was carried out to monitor the stress and displacement of the upper,middle and lower parts of the grouting section.At the same time,the variation and distribution of soil stress and displacement in different directions with grouting pressure were discussed.The results show that the slurry diffusion range increases with the increase of grouting pressure and time,up to 2.12 m;the error between the simulated value and the measured value is less than 15%when the grouting time is 10 min.The maximum displacement of the soil after 30 min is 5.53 mm,and the soil can remain stable under different working conditions.The recommended grouting pressure is 0.5～0.8MPa and the grouting time is10～20min.（3）Based on the performance of composite grouting material and numerical simulation results,a complete set of grouting construction technology is formed.Based on the previous research results,according to the plum blossom shape,the grouting hole spacing is determined to be 2.5～3.3m,the grouting pressure is0.5～0.8MPa,and the grouting amount can be calculated according to the formation condition.A complete set of construction plan including construction preparation and construction technology is formulated.Construction preparation includes seven aspects such as geological exploration.Construction technology covers eight links from hole positioning to grouting effect detection.