Mix Proportion Design And Performance Study Of Composite Aggregate Permeable Concrete

At present,the pervious concrete is a kind of green,ecological,environmental protection material,has very important and realistic significance for the research on the development and construction of the city,and the research and application of pervious concrete in our country is still in the initial stage,especially for the research of pervious concrete composite aggregate is less in strength,coefficient of permeability and durability other aspects have not formed a complete research system,but the development and application of the composite aggregate porous concrete has played a key role.Therefore,we have made a series of researches on the preparation,mix proportion design,permeability coefficient,porosity,compressive strength,freeze-thaw cycle and plugging mechanism of composite aggregate permeable concrete.The specific content of the work is as follows:(1)the best mix proportion of pervious concrete with composite aggregate was studied by selecting pumice,recycled concrete and gravel.A single variable test was carried out to determine that the aggregate size was 4.75-9.5mm and the amount of water reducing agent was 0.4%.With 15% porosity as the design target,the optimum mix ratio was designed by orthogonal test,and the optimum mixture ratio was obtained.The optimum parameters were the ratio of water to glue 0.27,aggregate ratio 1:1:2,fly ash.The dosage is 15%,the strength is 21.7MPa,the permeability coefficient is 1.48mm/s,and the pore measurement is 15.1%.(2)A preparation method of composite aggregate permeable concrete was proposed.The main consideration of aggregate water absorption effect,the preparation process of cement slurry to avoid the bottom problem,while preparing the specimen and the effect of performance than the traditional preparation process is better,which according to the determination of aggregate water absorption rate,in the preparation process,need to add additional water amount as the aggregate water absorption rate70-80% is the best,this study obtained 75% water absorption performance is better.(3)The optimum content of iron tailed ore is studied and put forward.Mainly studied the incorporation of iron ore tailings,compared with the performance of non sand,sand under the strength and permeability coefficient were improved,the porosity remained unchanged,the rate of sand content is 25%,the best effect,the porosity is 15.5%,the coefficient of permeability to 1.95mm/s strength up to22.8MPa.The design and selection of the best mixture ratio were carried out.Finally,the sand free composite aggregate permeable concrete was identified as three groups,and the sand composite aggregate permeable concrete is a group.By orthogonal experiment,the influence of three factors,such as water binder ratio,fly ash content and aggregate ratio,on the performance is analyzed,and the fitting relationshipbetween permeability coefficient and strength is obtained.(4)the fitting curve of the composite aggregate permeable concrete is studied.According to the results of the test,the fitting relation of the permeability coefficient and strength of the composite pervious concrete is mainly carried out,and the fitting equation is obtained.(5)the frost resistance of composite aggregate permeable concrete was studied,and 100 freezing and thawing tests were carried out on five groups of specimens.The ratio of water to glue was 0.27,fly ash was 15%,the ratio of the proportion of aggregate 1:1:2 to the ratio of freezing and thawing could reach 75 times,and the content of iron tail mineral sand was 25% to 100 times left right,and the other groups all reached 50 freezing and thawing cycles..(6)the clogging experiment of composite aggregate permeable concrete was studied,and the anti blocking grade of the composite pervious concrete was two.The experiments were conducted to study the blocking composite aggregate pervious concrete,experimental scheme and anti clogging level through design and develop of the anti clogging situation judgement,which determine the data mainly based on the permeability coefficient were divided,and put forward the reasonable maintenance and cleaning,and according to the different anti clogging maintenance method is proposed for different grades to explore,and to study the role of composite aggregate pervious concrete,has high significance.