Through the experiment, this paper studies and analyzes influence of different initial temperatures on cement grout performance. The results show initial temperature has influences on grout fluidity, bleeding rate, setting time and early strength. Under guaranteed curing temperature, initial temperature has no influence on long-term strength of grout.
In order to systematically study dynamic mechanics character of reactive powder concrete (RPC), impact compression experiments and impact flattened Brazilian disc specimens of RPC have been investigated with modified split Hopkinson pressure bar (SHPB) experimental facility using brass pulse shaper, curves about stress versus strain and other parameters at strain rates of 20.3/s~137.0/s were obtained from impact compression. The dynamic tensile strength and tensile failure strain at strain rates of 3.4/s~26.2/s were obtained from impact flattened Brazilian. For comparison, the quasi-static compress and split tension of RPC were obtained with an MTS 810 materials test system and CSS-88500 electron universal material testing machine.The experimental result show that dynamic compression strength , elastic modulus and failure strain,dynamic tensile strength and failure strain significantly increase comparing to quasi-static experiment, RPC have the character of impact harding and ductility enhancement. RPC exhibit excellent failure patterns at high strain rate. Whether impact compression or impact splitting under strain rate including this paper ’s experiments, the relationship between the DIFC or DIFT and the logarithm of strain rateis linear.
According to the principle of Preparation about Reactive powder concrete (RPC),selection of local raw materials,the use of orthogonal experimental design method,carried out research of RPC mixing proportion design. Finally get the RPC optimal mix of meeting engineering requirement. By the range analysis and variance analysis of the test data of mix,obtained the influence law about water-cement ratio,steel fiber content, sand type,curing regime on compressive strength and splitting tensile strength .
Explosion containment structure (chamber) is used to protect personnel and experimental equipment during the destruction of explosion environmental for research blasting or disposal exploder. Reinforced concrete has advantiage of low cost and simple process in buliding ,so it was usually used of buliding the structure of resist explosion.This paper demonstrates reinforced concrete structures character of resist explosion under envirmonent of filling sand,the hoop strain of structure central cross section were measured loaded by different mass explosive charges,the safe criterion of reinforced concrete structure was obtained. Loaded by the explosion,the damage mechanics of reinforced concrete structure that diameter equal to height was analysed,and the method for avoiding the structure fail was suggest.
The gas permeability of polymer modified mortar coating add steel fiber concrete compound structure was studied by thickness-wall cylinder structure experiment. The coatings were characterized by scanning electron microscope,energy-dispersive X-ray spectroscopy.the gas permeability of steel fiber concrete is 6.85×10-15 m2. applying the coating can reach 10-17 m2. The intrinsic gas permeability of polymer modified cement based materials is 1.36×10-17 m2 using regression calculate analysis method .Coating thickness is constant, raw materials composition and structure is the fundamental factors affecting permeability.
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