Experimental Study On Pervious Concrete Made From Recycled Aggregate Mixing With Basalt Fiber

With the speeding up of urbanization and industrialization,the surface of the city is covered with reinforced concrete buildings and impervious surface,which resulting in a series of urban environmental problems such as urban waterlogging and lower groundwater level during the rainstorm season.Recycled aggregate porous concrete have many effective functions:protecting and saving water resource,relieving urban heat island effect,absorb sound and reducing noise,saving energy resources.As a new type of ecological environmental protection building materials,has wide application prospect of roads of residential quarters,square and park.Basalt fiber can improve anti-cracking performance of concrete and improve the frost resistance of concrete.In this paper,experimental study on the18mm and 24mm in length,diameter of 15um dosage and length to diameter ratio of two kinds of basalt fiber opposite the performance impact of recycled aggregate porous concrete is studied.The influence of content and length to diameter ratio of basalt fiber on porosity and permeability coefficient is studied.As the increase of fiber content,permeable concrete porosity and permeable coefficient of recycled aggregates are lower,but still can meet the requirements of specification.The increase of fiber length to diameter ratio can inhibit lower porosity and permeable coefficient.The influence of fiber content and length to diameter ratio on tensile strength and flexural strength is studied.Study found that,with the increase of fiber content,three mechanics performance index have show trends of increased first and then decreased.Through analysis obtained the result that fiber content should be controlled in 4kg/m~3.The increase of fiber length to diameter ratio can improve the mechanical properties of recycled aggregates permeable concrete.Under the comprehensive consideration,when fiber length is24mm,4kg/m~3 for fiber content,basalt fiber water recycled aggregates concrete can obtain better mechanical properties.Under different freezing and thawing cycles,through the analysis of fiber content on the loss rate and the compressive strength loss of recycled aggregates permeable concrete,found that the mixed basalt fiber can effectively inhibit the mass loss rate and the decrease of compressive strength after the freeze-thaw cycle.Adding 24mm fibers in recycled aggregate porous concrete has better effect on suppressing of compressive strength reduction after the freeze-thaw cycle.