Research On Dredging And Clogging Technology Of Permeable Concrete

Permeable concrete is a kind of eco-environmental protection concrete made by special technology,which has good water permeability,noise reduction and heat absorption ability,and is the key material for the construction of"sponge city".During the service period of pervious concrete,the surface runoff is mixed with silt and other impurities,which is easy to block the internal pores of pervious concrete,resulting in the reduction of drainage capacity of pervious concrete,and even the loss of pervious concrete capacity.To solve the problem of pore clogging of pervious concrete,pervious concrete with different porosity and different aggregate size was prepared.By studying the change of permeability coefficient and residual permeability permeable concrete,discusses the blocking process of waterproof concrete,the permeable concrete main design parameters,such as design,sand aggregate particle size,particle size,porosity,plugging material types,such as oil and algae growth,influence on permeable concrete pore jams,reveals the plugging mechanism of waterproof concrete.Based on the experimental study,a mathematical regression equation is established to evaluate the degree of permeability attenuation of pervious concrete.Based on digital Image processing technology,Image J software is used to analyze the two-dimensional plane pore structure of pervious concrete,and the functional relationship between pore structure characteristics and permeability of pervious concrete,as well as the influence of pore size on plugging is discussed.Finally,manual cleaning,pressure washing,vacuum suction and the combination of manual cleaning and high pressure washing were used to maintain the blocked pervious concrete.The recovery rate of permeability coefficient was used as an index to evaluate the advantages and disadvantages of each maintenance measure.The results show that:（1）The influence degree of particle size and porosity of blockages on the permeability coefficient of pervious concrete is different.（2）When the particle size of the blockage is small but the aggregate size is large,the blockage of pervious concrete is not easy;When the blockage particle size is larger and the grading is better,the larger aggregate size is not conducive to the anti-plugging ability of pervious concrete.（3）Sand and vehicle lane impurities have the most serious influence on the blockage of pervious concrete,and oil pollution speeds up the attenuation rate of pervious coefficient;The growth of algae on the surface of pervious concrete reduces its water permeability.（4）The holes in pervious concrete are mainly tiny and slender holes.Under the same aggregate size,the larger the porosity,the larger the number and size of pores in pervious concrete.At the same time,the larger the aggregate size,the wider the distribution of pore size.Pore area can better predict the permeability of pervious concrete than pore equivalent diameter and pore boundary length.（5）The clogging degree of pervious concrete is affected by the ratio of clogging particles to pore size.When the values of?,?₁ and?₂ are within the interval of 0.06-0.14,0.10-0.20 and 0.03-0.06,respectively,the pervious concrete is more likely to be blocked.（6）All the maintenance measures proposed in the study can restore the water permeability of the blocked pervious concrete to a certain extent,and the combined measures of manual+pressure washing have the best effect.