| Over time,more and more old buildings appear structural aging,resulting in the structural safety margin reduction,so the maintenance,reinforcement and reconstruction of these old buildings are necessary.In the reinforcement and reconstruction technology,because of the flexible construction technology,the embedded steel bars technology can effectively solve the problems of unstable embedded parts,the position deviation caused by construction negligence,and the connection of new and old concrete,and it has been more and more widely used.The first thing to consider in the embedded steel bars technology is the adhesive,which is divided into organic planting glue and inorganic planting glue.At present,most of the adhesives used at home and abroad are organic glue,but this material has some problems in the actual construction process,such as long setting time,the hole of planting bars that must be dry and anhydrous,poor heat resistance,and poor durability.In view of the above-mentioned defects of organic adhesive,a new type of rapid solidified and high strength alkali activated inorganic glue was developed in this paper.In this thesis the mechanism of the bond anchorage was analyzed at first,the typical failure mode and the calculation formula of the ultimate bearing capacity of the steel bar were summarized,and the many factors that affect the performance of the planting bar were studied,the research and analysis show that the performance of the adhesive is very important in the anchorage.Alkali-activated cementing material is an inorganic cementitious material developed in recent years,the composition and mix proportion of raw materials all have a great influence on the strength performance,condensation performance and bond anchorage performance of cementitious materials.In this paper,blast furnace slag and fly ash as the main raw materials,sodium silicate and sodium hydroxide as the excitant,through the multiple mixing proportion test,comprehensive consideration of compressive strength and setting time,determine the optimal mix proportion of a group of inorganic adhesive.Through anchorage drawing experiment on concrete base material,the bond anchorage performance of new type of alkali activated inorganic adhesive was tested.The influence of different rebar diameter,anchorage depth and number of steel bars on the ultimate bearing capacity of inorganic adhesive bars was studied,and load-displacement curves were obtained.Referring to the research of scholars at home and abroad,and according to the test phenomenon and specifications,this paper putsforward the economic anchorage depth of the economic anchorage of this inorganic adhesive.The durability of inorganic adhesive is not related to the technology of embedded steel bar in China at present,and this paper studied the long-term bond anchorage performance of new inorganic adhesive by comparing the results of the anchorage drawing experiment of inorganic adhesive bars and organic adhesive bars under the same conditions.The experimental results show that the adhesive anchorage performance of alkali slag inorganic adhesive is good,and its durability is obviously better than organic adhesive.Finally,the inorganic adhesive was used for the placement of the shear pin in the HPFL.According to the experimental results of the HPFL strengthing,concrete members,the ratio relationship between the maximum tensile force and the ultimate tensile force was obtained by the mathematical method and the results analysis,and the planting qualified value of the shear pin was defined in combination with the engineering practice,which provides an important reference for the evaluation of the quality of the shear pin.The inorganic planting glue was used in the reinforcement project of the mineral processing pool after the fire,the ultimate bearing capacity of the shear pin was obtained through the field sampling,and the test results show that the rebar planting effect of this inorganic planting glue in practical engineering can achieve the expected expectation. |
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