Study On Preparation And Properties Of Radiation Protection Concrete

China will vigorously develop nuclear power industry from 2016 to 2020.As a radiation proof concrete for the construction of nuclear facilities safety shell and shield wall, there are a lot of researches at home and abroad. Comparatively speaking, foreign research has theoretical depth as well as a large number of experimental basis. And Europe, the United States, Japan and other countries have the corresponding anti radiation concrete, anti radiation shielding shell structure, nuclear waste disposal and other standards. In our country, there are a lot of experimental foundation in this field, but it still needs to be studied and summarized.This paper studied hard boron calcium powder effect on anti radiation concrete setting time, Mechanical properties, durability, when acting as neutron absorber. Studied barite, magnetite and hematite as aggregate effect of anti radiation concrete strength(Compressive, splitting tensile, axial compression, elastic modulus), Long term durability(Anti permeability, anti carbonation, chloride ion erosion, sulfate resistance, frost resistance, salt resistance and frost resistance), Workability.In order to enhance the anti radiation concrete density using steel balls, steel grit, steel section aggregate.Due to different particle sizes, different size, different levels of the mechanical and durability effects. Test results are as follows.1. Hard calcium boron powder as a neutron absorber was used in radiation protection concrete. Powder content less than 20 kg/m3 for setting time of concrete and the mechanical properties of impact can be ignored. When hard calcium boron powder content higher than this value will be obvious reduce setting time and reduce strength;2. Barite fragile texture which can make 20Mpa~40Mpa strength of radiation protection concrete; Magnetite and hematite is hard, which can act as 60 Mpa radiation protection concrete aggregate.3. The experiment show that heavy aggregate's absorbent affect the setting time of radiation protection concrete,Hematite use as aggregate lead concrete setting time earlier than blank group, and earlier shrinkage value.4. Under the precondition of satisfy the mixture density, reasonable use grading system of aggregate, dosage of water reducing agent, appropriate mixture slump around 180 mm still can ensure good working condition and good workability, do no segregation no exudation let stand no delamination.5. Ore heavy aggregate and steel aggregate of concrete carbonation resistance had no significant effect. Barite obviously cause permeability resistance, freeze resistance, salt resistance and frost resistance reduced. Steel aggregate significantly reduce concrete freezing-thawing resisting ability. Hematite aggregate 10 s pressure bleeding rate is half of barite group; Hematite group after 28 times salt frozen, mass loss of 357 g/m2, the value of about 1/2 limestone group.6. Steel aggregate grain shape, gradation distribution affect the radiation protection concrete strength. Adopting the different particle size distribution of crushed slag steel group aggregate strength is greater than the different particle size distribution of round steel aggregate strength is greater than the single particle size long pillar shape group strength is greater than the strength of single spherical particle size group. Steel aggregate mixed with appropriate ratio to replace sand, stone, such as at the same time can guarantee the strength. Steel aggregate after incorporation will cause the concrete elastic modulus increase. Design C30 strength, bulk density of 4000kg/m3, the use of steel aggregate on the grip force no effect; Using steel concrete aggregate will make internal cement- steel aggregate interface transition zone becomes weak, the strength reduction. By reducing water-binder ratio 0.02 can make up for the strength of weak interface fell;7. Hematite will cause the radiation protection concrete early larger shrinkage, 72 h shrinkage rate 1583?m/m, and a significant increase at the early stage of the test. Barite group has the smallest shrinkage, its value is smaller than hematite group 34%. Steel aggregate because their elastic modulus, non-absorbent two reasons, adding to the radiation protection concrete can reduce the early plastic shrinkage.