Study On Mechanical Properties Of Basalt Fiber Recycled Concrete

With the development of society,the concept of green development has taken root i n people&apos hearts,and the treatment and reuse of construction waste has received att ention.In particular,turning waste concrete materials into valuable materials for reuse h as gradually become a hot topic of research by scholars.The recycling and reuse of cons truction waste can effectively save land resources,promote the development of green cit ies and green economies.For recycled aggregate,its poor mechanical properties make it difficult for recycled concrete with a certain replacement ratio of recycled aggregate to be applied in practical projects.However,the addition of basalt fibers can limit the deve lopment of cracks to a certain extent and effectively improve the mechanical properties of recycled concrete.Basalt fiber has high tensile strength,strong corrosion resistance,a nd low cost.It is a green,environmentally friendly,high-performance fiber material,an d has gradually become a research hotspot in the field of fiber reinforced concrete mater ials in recent years.This paper analyzes the strengthening and toughening effects of bas alt fiber on recycled aggregate concrete through indoor experiments,and explores the i mpact of basalt fiber on the mechanical properties of recycled aggregate concrete from a spects such as fiber content and age.The results are as follows:(1)Conduct slump tests of recycled concrete with different basalt fiber content,an d study the impact of basalt fiber content on the working performance of recycled concr ete.The results show that: The addition of fibers significantly reduces the fluidity of rec ycled concrete.When the fiber content is greater than 0.3%,the workability of the mixt ure cannot meet the subsequent experimental requirements.Increasing the amount of wa ter reducing agent can effectively improve the workability of recycled concrete.(2)Using fiber content and age as variable parameters,indoor tests on compressive strength,splitting tensile strength,and flexural strength of recycled concrete were cond ucted.The test results showed that basalt fiber had a significant impact on the strength o f recycled aggregate concrete.Based on the test data,it can be seen that basalt fiber dim ension increased the compressive strength by between 3.0% and 8.6%,with a maximum increase rate of less than 10%;The increase in tensile strength is between 11.16% and 30.28%,with a significant improvement effect;The increase in flexural strength is betwe en 0.3% and 16.2%,and the improvement effect is between compressive strength and te nsile strength.Comparative analysis of the basic mechanical properties of recycled aggr egate concrete at different ages and research on the early strength growth rule of fiber re inforced recycled concrete shows that basalt fibers have a certain effect on the early stre ngth growth rate of recycled concrete.Based on experimental data,it can be seen that 0.2% fiber content has the most significant effect on the strength growth rate of recycled c oncrete.(3)Uniaxial and conventional triaxial tests of recycled concrete were conducted to study the mechanical properties of basalt fiber reinforced recycled concrete under uniaxi al and multiaxial stress conditions,using lateral confining pressure and fiber volume co ntent as variables.The results showed that the restraining effect of lateral confining pres sure on the specimen greatly weakened the impact of fiber on the mechanical properties of recycled concrete.Combined with the test results,the peak stress Strain and elastic m odulus are analyzed,and relevant index calculation formulas are given based on data.(4)Based on experimental data,a constitutive relationship model of complete stres s-strain curve for basalt fiber reinforced recycled concrete under uniaxial and conventio nal triaxial conditions is established.The results show that lateral confining pressure an d fiber content have little impact on the shape of the curve rising section,while the curv e falling section changes significantly with the application of confining pressure.The ca lculation formulas for compressive strain energy and brittleness index of recycled concr ete are obtained through calculation.With the increase of confining pressure,the compr essive strain energy of recycled concrete gradually increases,while the value of brittlen ess index significantly decreases after applying confining pressure.