Study On The Preparation And Durability Of Waste Fiber Recycled Concrete

As an environmentally friendly building material,waste fiber recycled concrete is beneficial to consume a large amount of construction waste and waste fiber,and is also beneficial to solve the problems inherent in concrete.Sulfate corrosion resistance and impermeability are durable as concrete.An important part of sexual research,it is necessary to conduct in-depth research.The dry-wet cycle test and gas permeation test of sulfate were used to study the mechanical properties,sulfate attack resistance and impermeability of recycled fiber recycled concrete with different recycled aggregate replacement rate,waste fiber content and water-cement ratio.The law of influence is observed,and the microstructure of the concrete is observed by XRD analysis,scanning electron microscopy analysis and concrete section hole spacing analysis.The results show that:The replacement ratio of recycled aggregate has a significant effect on the strength of recycled fiber recycled concrete.The replacement ratio of recycled aggregate is less than 50%,which will not significantly reduce the compressive strength of recycled concrete.When the aggregate is composed entirely of recycled aggregate The compressive strength of recycled concrete decreased significantly,and the compressive strength of 28 d,45 d,60 d and 75 d decreased by 13%,8%,20%and 21%,respectively.It can be seen that the completely recycled aggregate concrete has defects in long-term mechanical properties,and the strength decreases greatly;the incorporation of waste fiber has no obvious effect on the improvement of concrete compressive strength,and the excessive amount of waste fiber is harmful to the compressive strength of concrete;Reducing the water-cement ratio of concrete within the range is beneficial to increase the compressive strength of concrete.In the initial stage of the sulfate attack process,the anti-sulphate corrosion performance of the waste fiber recycled concrete is improved.After 15 dry and wet cycles,the corrosion resistance coefficient of the waste fiber recycled concrete reaches 117%,and continues with the number of dry and wet cycles.Increased,the anti-sulfate corrosion performance of waste fiber concrete deteriorates;the greater the replacement rate of recycled aggregate,the worse the sulfate resistance of waste fiber recycled concrete,and the resistance of sulfate to concrete is 50%or less.The erosion performance is not obvious;within the reasonable range of water-cement ratio,appropriately reducing the water-cement ratio of concrete and incorporating a certain amount of waste fiber is beneficial to improve the sulfate-resistant performance of waste fiber recycled concrete.The amount of waste fiber is 0.02%?0.04%is the best.Recycled aggregate replacement rate,waste fiber content,water-cement ratio and other factors will affect the impermeability of waste fiber recycled concrete.When the replacement ratio of recycled aggregate is less than 50%,the impermeability of concrete does not show a significant decline.When the replacement ratio of concrete recycled aggregate is 100%,the impermeability of concrete decreases greatly;0.02%?0.04%of waste fiber is added to improve the impermeability of waste fiber recycled concrete,and the amount of waste fiber continues.Increases can have a detrimental effect on the impermeability of concrete.Through SEM,XRD,concrete cross-sectional hole spacing analysis and other microscopic test analysis,in the initial stage of sulfate attack,a certain amount of expansion products are produced inside the concrete,which is beneficial to improve the internal structure of the concrete,incorporate a certain amount of waste fiber,and the internal pores of the concrete are obtained.Improved,impermeability and resistance to sulfate attack are improved.