Research On Mechanical And Carbonization Properties Of Mineral Admixtures And Basalt Fiber Concrete

With the rapid development of bridge engineering,railway engineering,and super high-rise buildings,high-performance concrete came into being.Mineral admixtures are used as cementing materials to replace part of cement.On the one hand,reducing CO₂ emissions in the cement production process,and on the other hand,improve the compactness and mechanical properties of concrete through their filling and active effects.Basalt fiber（BF）has high toughness,tensile strength and other properties.Incorporating BF into concrete inhibits the generation and development of concrete matrix cracks,thus improving the splitting tensile strength and flexural strength of concrete.Therefore,the research on the mechanical properties and anti-carbonization performance of concrete mixed with fly ash（FA）,silica fume（SF）and basalt fiber not only has the significance of resource recycling and reuse,but also provides experimental value for the development of improved cement-based materials.In this paper,through orthogonal experimental design,the influence of three modified materials of FA,SF,and BF on the mechanical properties and carbonization properties of concrete is studied.FA and SF adopt internal mixing method to replace part of the cement,the mixing amount of FA is 10%,20%,30%,the mixing amount of SF is 2%,4%,6%;the BF is externally mixed Method,the dosage is 0.15%,0.30%,0.45%.The following conclusions are obtained through the experiment:（1）At the same age,with the increase of FA content,the mechanical strength of concrete will decrease.The designed content of SF is conducive to the improvement of concrete mechanical strength.Too much BF will easily lead to uneven dispersion.,Resulting in a decrease in the mechanical strength of concrete.（2）When the content of FA is 30%,the mechanical strength of concrete at 3d,7d,and 28d ages at all mix ratios is lower than that of the benchmark concrete.Therefore,when the content of FA is 30%,it is important to increase the strength of concrete.negative effect.（2）Through the analysis of extreme difference and factor index,the content of FA in concrete is 10%,SF is 6%,BF is 0.45%,which is the best content to improve the compressive strength,split tensile strength and flexural strength of concrete.Compared with plain concrete of 28 days maintenance age,the content of FA in concrete is increased by 3.98MPa,0.58MPa and 1.05MPa,with the improvement rate of 6.1%,18.1%,13.3%.（3）Under the same carbonization age,as the content of FA,SF,and BF increases,the carbonization rate of concrete gradually increases.It shows that when the content of FA is 10%,the content of SF is 2%.,When the content of BF is 0.15%,the performance of 28d anti-carbonization of concrete is the best.