Study On Preparation And The Attenuation Of Pervious Performance Of Recycled Aggregate Permeable Concrete

Recycled aggregate pervious concrete is a concrete with water permeable function made of recycled aggregate from construction waste.The application of RPC on the one hand can solve the problem of construction waste in the process of urbanization,and reduce the amount of natural materials;on the other hand,RPC has a waterproof,sound-absorbing,cooling and other characteristics,its application is conducive to resolving the influence of city waterlogging,and city heat island effect on Ecological environment.With the promotion of "sponge city",the deepening of low impact development concept and the importance of urban hydrologic environment,RPC will rapidly cover every aspect of the city.In daily life,any road will inevitably exist sediment particles,due to multiaperture of RPC,these particles would get into inside of RPC or pile up in surface pores of RPC by natural sedimentation,rainfall and other reasons,leading to attenuation of RPC permeability,which is unable to avoid the problems in the process of its application.In addition,during the early preparation of RPC,it was found that the rheology of cement paste had a great impact on RPC,which may lead to a significant decrease or even loss of RPC permeability.The blockage mechanism mainly takes into account the effect of the blockage of the material category and the particle size of the blockage.Slight blockage(adding 10 g blockage in each cycle)mainly considered the influence of porosity and blockage category.Severe blockage(adding 40 g blockage in each cycle)mainly considered the influence of cleaning way,porosity and blockage category,The results of the test are as follows:(1)The research on Influencing Factors of RPC forming and permeation function shows that the fluidity of cement paste has great influence on the formation and permeability of RPC,and RPC with different porosity has different optimum fluidity range.(2)The experiment of osmotic attenuation mechanism shows that whether viscous particles have the greatest impact on the permeability coefficient of RPC is the most important factor.For the non cohesive blockage,the particle size distribution is the main factor.(3)the long-term cycle test showed that blockage type,porosity and repair method had significant influence on the RPC permeability coefficient,permeability decrease,the attenuation rate and recovery effect coefficient.Quantitative evaluation has been established about the attenuation of the permeability coefficient of RPC in the case of clogging by the attenuation rate of the permeability coefficient,the failure line of the water permeable function and so on.Beside,the effect of the common cleaning method on the recovery of water permeable function is compared.