Experimental Research Of Diatomite Porous Recycled Concrete Based On Surface Run-off Pollution Eco-treatment

With the development of society, the heavy traffic of various pollutants such as heavy metals、nitrogen and phosphorus compounds accumulated in the pavement,with rainfall into the soil and along rivers,causing ecological damage.Meanwhile, rebuilding houses and roads have produced construction waste,not only take up precious land resources,but pollute the environment.Based on diatomite as admixture of recycled concrete,The study focused on the compressive strength of diatomite recycled porous concrete,pavement run-off pollution treatment and plant adaptability.By choosing two kinds of diatomite as 100 and 150 mesh instead of 0%～30% cement into mortar, through testing and analysising influence of cement strength, to selected proper fineness of diatomite as admixture of concrete according to 28d compressive strength.By studying the preparation technology of porous concrete under different diatomite content,by the comparison and selection of layered insert pound and vibration molding,by using through compressive strength and Connected porosity as the index,combined with CT tomography surface pore structure,then select the optimum molding process under different content.By studying the sewage purification ability of mixing diatomite porous concrete,the experimental results showed that:when diatomite content reached 20%,the removal rate of Ammonia nitrogen, heavy metal pollutants improve significantly;the removal of SS mainly influenced by porosity;With the increase of concentration of pollutants,the purification ability of porous concrete are reduced;Flow velocity on the purification ability of porous concrete play an important role,The lower the flow velocity of pollutants is,the more obvious removal efficiency is.Concrete pore alkalinity significantly effects on plant’s growth,the experimental results showed that:With the increase of the dosage of diatomite,concrete pore basicity decreased,but the effect is not obvious;By comparing two methods of alkali reduction (immersion method and admixtures),the cycle of immersion method is long,alkalinity is in dynamic equilibrium,PH dropped to about 10.By adding ZS-2 type vegetation concrete admixture can reach better alkali suppression effect in 7 days.The results of perennial ryegrass planting experiment showed that the roots can penetrate the pores in 28 days,the growth has not been significantly affected.The results of mixed seeding test showed that:there is population competition between perennial ryegrass and bermudagrass.