Study On The Regular Pattern And Mechanism Of Granite Powder On Performance Of The Hydraulic Concrete

As one of the industrial wastes with the largest annual emissions and cumulative stocks,granite powder can cause resource waste and environmental pollution s due to its storage and processing in our country currently.Most water diversion and irrigation projects are mainly Water delivery channels.The mechanics and durability of the channel lining concrete deteriorate because of leakage,carbonization,freeze-thaw and other factors,affects the service life of agricultural water conservancy projects.To exploit granite powder as a building material to prepare hydraulic concrete for farmland water conservancy project is one of the efficient strategies to solve its pollution problems,improve the mechanics and durability of hydraulic concrete,and prolong the service life of water conservancy projects.Here,by combining with theoretical analysis,macro-physical test,and micro-test(MIP,SEM test)method together,this work is to study the different granite powder condition,such as(internal admixture,external admixture),different content(0?30%)and different fineness(I0?150?m;II,0?80?m),on the performance,mechanical properties and durability of hydraulic concrete..The results showed that granite powder with different mixing methods,content,and fineness could influence on the work performance,mechanical properties and durability of concrete.It was conclued that external mixing was the optimal mixture method,and the fineness is I(0?150?m)by comprehensive consideration of various influencing factors and performance indicators.According to this,the hydraulic concrete mixed with granite powder with a fineness of 0?150?m was taken as the research object here.The relationship between the microstructure characteristics(porosity,pore volume fractal dimension)of concrete mixed with granite powder and the compressive strength and durability of hydraulic concrete was explored with MIP and SEM experiments,The mechanism underlying the effect of granite powder on the performance of hydraulic concrete was revealed.The main conclusions are as follows:(1)The slump of hydraulic concrete gradually is enhanced with the the increased granite powder internal admixture,while the slump gradually is decreased with the increased external admixture.And performance of hydraulic concrete having fine Degree II is better than that with fineness I when hydraulic concrete is made of the same amout of the granite powder.(2)The compressive strength of hydraulic concrete gradually is decreased following the increasd he granite powder internal admixture,and the fineness has little effect on the strength.While with the increasing of the granite powder admixture,the compressive strength of hydraulic concrete is first increased at the first beginning and is decreased after that.The best compressive strength is at 22.5% granite powder content and the fineness has less influence on the compressive strength under the condition of external admixture granite powder.The compressive strength of hydraulic concrete with granite powder external admixture is significantly higher than that of hydraulic concrete with granite powder internal admixture.(3)The durability performance of hydraulic concrete(impermeability,chloride ion resistance,carbonization resistance and frost resistance)exhibits a trend of first increasing and then decreasing with the increased granite powder under internal and external admixturesThe best durability of hydraulic concrete is 7.5% using the granite powder internal admixture,and the fineness level II is better than the fineness level I,while the best durability of hydraulic concrete when the granite powder is 22.5% under external admixtures content,and the fineness level I is better than the fineness level II.(4)Here,by combining with the comprehensive analysis of macro performance,micro structure mechanism and the gray entropy correlation method,the results showed that under the same dosage,the effect of mixing method and fineness on the macroscopic properties of hydraulic concrete is: external admixture fineness I> external admixture fineness II> internal admixture fineness II> internal admixture fineness I.The best use way of granite powder is external admixture,fineness level I(0?150?m).(5)The stress-strain curves of hydraulic concrete with different granite powder content were analyzed,and the relative stress-strain constitutive relationship equation of hydraulic concrete was established,and the parameters were revised.(6)Considering the strength damage index,the relationship between the frozen-thaw strength damage of the granite powder external admixture and the number of frozen-thaw and the amount of granite powder is established.It is concluded that the key factors affecting the strength damage are freeze-thaw times>mass loss rate> the amount of granite powder through the analysis of gray entropy theory.(7)The pore structure of hydraulic concrete(porosity,average pore diameter,median pore diameter,critical pore diameter,most probable pore diameter,fractal dimension)show the trend of first decreaseing and then increaseing with the enhancement of the admixture of granite powder.With the increased fractal dimension,the total porosity is decreased,the pore level ratio is optimized,and the mechanical and durability properties of hydraulic concrete are gradually improved.The compressive strength,impermeability,resistance to chloride ion erosion,resistance to carbonization,and fractal dimension satisfy the power function relationship,however,conforms to a quadratic function relationship with porosity.(8)Analyzing the pore structure and interface characteristics of hydraulic concrete with MIP and SEM,it is revealed the mechanism of granite powder to hydraulic concrete is microcrystalline nucleus effect and filling effect which are optimized by the pore structure distribution,improvement of the integrity and compactness of the interface structure.The results have proved the influence and mechanism of granite powder on the performance of hydraulic concrete,solved the problem of resource utilization and environmental pollution of granite powder,and improved the mechanics and durability of hydraulic concrete at the same time.Taken together,the results are of great significance for the engineering application and theoretical research of granite powder in the field of hydraulic concrete in agricultural water and soil engineering.