| The typical cement matrix of cement concrete is the most important and irreplaceable construction material in modern civil engineering. However nowadays problems appear in its durability. The erosion of reinforcement is regarded as the main reason which cause the early destroy in the reinforced concrete construction. Since the chloride is the main cause of reinforcement erosion, it is important for the research of the permeability mechanism of chloride on composite material by cement matrix and the improvement of the anti-chloride permeability.There is experiment, which testifies that the introduction of ultra-fined mineral functional material and new super-plastic admixture can greatly improve the complex function of cement concrete. This article is based on this result. First it makes a systematic study of the component, the construction, particle size and the effects of some typical kinds of mineral functional material. Then it explicates their effects on the cement concrete durability, mainly as physical character, mechanical character and anti-chloride permeability. It focuses on the theory of the mineral functional materials' improving the anti-chloride permeability and the chloride binding. The main achievements of this article include:1) Use the technology of XRD,SEM,BET, laser particle size distributor etc to test the component, the construction, particle size distributor, specific surface etc of micro-silica, ultra-fined slag, high quality fly ash, meta-kaolin clay ,four types of the mineral functional material, theoretically analysis the functions which the four mineral functional minerals act on cement concrete, namely pozzolanicity effect, filling effect, micro-aggregate effect, surface adsorption effect and so bring into play the affect of plastification, lowing of temperature, reinforcement, improvement of durability. Base on this analysis we can conclude that the proper diameter of the mineral functional material is 5 μm-15 μ m, that is Blain fineness 4500cm2/g-7500cm2/g.2) The concept of mineral functional material is put forward, it discusses themanufacture technology of mineral functional materials with industrial waste, especially research on the feasibility of HPC's functional material by meta-kaolin.3) The experiment testifying the physical character and mechanical character of the cement concrete shows: how much the mineral functional material effects the physical character and mechanical character of the cement concrete is decided by the amount of the mineral functional material that we add. Proper amount of micro-silica, ultra-fined slag, high quality fly ash, meta-kaolin clay can improve the working ability ,hydration heat and strength(especially in the later period) of the cement concrete. Proper amount of meta-kaolin clay can do good to the strength of the cement concrete but verse to the working ability by magnifying water-cement ratio.4) The chlorides have three types of movement in the cement concrete: diffuse, capillary and permeate . We use ASTMC1202-94 rapid testing method of chloride permeability to testify the cement mortar, in which we add ultra-fined mineral functional material. The result shows that different kinds and different amount of mineral functional material with different component can affect the cement concrete's anti-chloride permeability differently. Usually the effect of multi-added is better than that of single-added. The separate addition of micro-silica, ultra-fined slag, high quality fly ash can improve the cement concrete's anti-chloride permeability. The result is micro-silica grater than slag grater than fly ash, and the greater the amount that added the greater the improvement is. However in this experiment, because of the overdose and the dampening of the mineral functional material the single-added of meta-kaolin clay did not result as what we expected. But when added together with certain amount of micro-silica its activity is seemed to improve greatly, also is the cement concrete's a... |
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