Study On The Application Of Pervious Mixed Recycled Aggregate Concrete In Road Engineering

The landfill and stacking of construction waste will cause a series of environmental pollution problems.Waste concrete and waste bricks will be crushed and used as mixed recycled aggregate for concrete production.Compared with the traditional concrete pavement,pervious concrete pavement can collect rainwater,replenish groundwater resources,adjust the surface air temperature and humidity,alleviate the urban heat island effect,and to improve people's living environment.It can provide a broader market for recycling and utilization of construction waste to research on pervious mixed recycled aggregate concrete and its application.The main contents and main conclusions are as follows:(1)The first part is the basic performance test of pervious mixed recycled aggregate concrete.On the basis of CJJ/T 135-2009 Technical specification for pervious cement concrete pavement,using mixed recycled aggregate,design ideas based on orthogonal test,respectively considering 5 influencing factors,including the water cement ratio,target porosity,the amount of silica fume,molding pressure and aggregate gradation,test the effective porosity,the compressive strength,the flexural strength and permeability coefficient of pervious mixed recycled aggregate concrete different levels of the influencing factors,and constantly to optimize its performance,study on the reasonable proportion of mixture of pervious mixed recycled aggregate concrete.The results show that: when the water cement ratio is 0.3,the target porosity was 18%,the amount of silica fume is 9%,molding pressure is 1.5 MPa,the amount of aggregate particle size of 10-15 mm is 25%,the properties of pervious mixed recycled aggregate concrete is excellent.The compressive strength is 21.19 MPa,the flexural strength is 3.66 MPa,the coefficient of permeability is 2.63 mm/s,these results meet the requirements of each index of CJJ/T 135-2009 Technical specification for pervious cement concrete pavement.(2)The second part is the road performance test of pervious mixed recycled aggregate concrete.The test pavement is paved according to the mix ratio scheme achieved from the first part of the test for further research.The test results show that: when the pavement is rolled for 4 times,the compressive strength is 14.65 MPa,the coefficient of permeability is 1.12 mm/s;and when the pavement is rolled for 6 times,The compressive strength is 17.84 MPa,the coefficient of permeability is 0.83 mm/s,and the strength does not meet the requirements of CJJ/T 135-2009 Technical specification for pervious cement concrete pavement.