Study On Road Properties Of Recycled Aggregate Porous Concrete

Recycled aggregate pervious concrete is a kind of porous concrete, which refers to the use recycled aggregate instead of natural aggregate, mixing with water, cement. It does not contain fine aggregate. Recycled aggregate porous concrete used for pavement material can solve the environmental problems caused by building waste, reduce the resources consumption, also can alleviate the lack of water resources in chinaThis paper studies the basic physical and mechanical properties of recycled aggregate and the mechanical property, water permeability, frost resistance permeability of the recycled aggregate pervious concrete. To develop the road recycled aggregate pervious concrete both meet strength, durability and water permeability requirements.Recycled aggregate pervious concrete mixture ratio design use the method mix with roller compaction concrete and the method of volume combines. Because of the large Water absorption of recycled aggregate required to consider the additional amount of water when mixture ratio designing. The orthogonal test was designed considering four parameters including water to cement ratio, cement content, grain series of recycled aggregate and aggregate to cement ratio, each parameter was set at three levels. Such performances of porous concrete were measured as cubic compressive strength, flexural strength, continuous porosity and water penetration coefficient. The ranges of every test parameters are also proposed. The factors which impact on mechanical property greater are Water-cement ratio and aggregate to cement ratio. The greater impact of water permeability is grain series of recycled aggregate. But the strength of concrete is low.Take certain improvements for the low strength of recycled aggregate pervious concrete: to maintain the water-cement ratio unchanged, increasing the amount of cement, improve the grain series of recycled aggregate to make the aggregate more dense, strict control additional amount of water which the recycled aggregate absorbed, the pressure of weight curbing increasing by5kPa to the10kPa. To study the influence of mechanical performance and water permeability of recycled aggregate pervious concrete by water-cement ratio, cement content and grain series of recycled aggregate. Result to the following laws:the recycled aggregate pervious concrete compressive strength and flexural strength increased with the increase of the amount of cement content and the water-cement ratio and the packing density of the recycled aggregate. Porosity of recycled aggregate pervious concrete between15%and25%, it can meet permeable performance requirements.The frost resistance of recycled aggregate pervious concrete use the slow freezing method. The frost resistance of recycled aggregate pervious concrete is relatively poor, but the mass loss rate did not exceed5%. Frost resistance of recycled aggregate pervious concrete increased with water-cement ratio and cement content and packing density of the recycled aggregate. The frost resistance and the mechanical properties of recycled aggregate pervious concrete have a positive correlation. When the cement content of320kg/m3, water-cement ratio of0.35, grain series of recycled aggregate of2, the frost resistance of recycled aggregate pervious concrete is better,after25freeze-thaw cycle it is still destruction.