Study On Properties Of Self-compacting Barite Concrete Based On Orthogonal Test

Barite concrete has a high apparent density and a good shielding effect against X and ? rays.It is widely used in nuclear power,national defense and medical engineering.With the rapid development of nuclear technology applications,radiation protection is particularly important.Currently,shielded construction projects mostly use modular construction technology to improve the integrity of the structure,and a large number of reinforced parts,connectors and system pipes are arranged inside the module,resulting in a narrow operating space,ordinary barite concrete is difficult to vibrate and compact,which brings serious risks to the shielding effect of concrete.Self-compacting concrete is a kind of concrete that can be filled without vibration under the action of its own gravity,It is suitable for buildings with dense steel bars and complex structures.In this thesis,a self-compacting barite concrete with high fluidity and anti-radiation properties is obtained through research,which can not only solve the problem that ordinary barite concrete is difficult to vibrate and compact in shielding construction projects,but also shorten the construction period and improve the construction environment.To make the barite concrete more widely used in the construction of shielding projects such as nuclear power,national defense and medical treatment,this research has certain practical application value.Aiming at the problem is that barite has a very high density and is prone to aggregate sedimentation leading to concrete segregation,this thesis adopts a method of mixing fly ash,cathode ray tube(CRT)glass powder and continuously grading the barite coarse and fine aggregate.The orthogonal test method was used to study the effect of water-binder ratio,water reducer dosage and sand rate on the working performance,mechanical properties and radiation protection performance of concrete,determine the optimal mix ratio,and successfully prepare self-compacting barite concrete,and the CFD software was used to numerically simulate the V-funnel test of self-compacting barite concrete based on the Herschel-Bulkley model.The main conclusions are as follows:1.The efficiency coefficient method was used to comprehensively evaluate the slump,expansion degree,T500 and V-funnel time of self-compacting barite concrete,and the optimal mix ratio was obtained as follows: water-binder ratio 0.43,water-reducing agent dosage 2.3%,sand rate 45%.The specific mix ratio is cement: fly ash: CRT glass powder: barite sand: barite coarse aggregate: water = 1:0.30:0.23:3:88:4.74:0.56.2.According to the relationship between orthogonal test factors and indicators,as the water-binder ratio increases from 0.42 to 0.44,the V-shaped funnel time and compressive strength of self-compacting barite concrete decrease,and the T500 of concrete,radiation protection performance first decrease and then increases;the amount of water reducing agent increases from 2.3% to 2.5%,the slump of concrete,T500 and V-funnel time first decrease and then increase,the radiation protection performance increases and then decreases,and the compressive strength continues to decrease;sand rate from 45% to 47%,the workability and radiation resistance of concrete continue to decrease,and the compressive strength gradually increases.3.The most influential factor on the slump of self-compacting barite concrete is the amount of water reducing agent,and the most influential factor on the T500,V-shaped funnel time and compressive strength is the water-binder ratio,which has an effect on the expansion degree and radiation resistance the most influential factor is sand rate.4.The CFD numerical simulation adopts a structurally divided grid,and simulation is calculated based on the unsteady-state implicit separation of pressure.By comparing and analyzing the simulation results and the experimental data,it is concluded that the rheology of the concrete test and simulation is basically the same,The correlation between the passing time of V-shaped funnel test and the passing time of numerical simulation is over 0.9,and the data are basically consistent,It shows that the CFD software can simulate the V-shaped funnel test of self-compacting barite concrete based on the H-B model.