A Study On The Dispersion And Mechanical Properties Of Short-cut Carbon Fiber Reinforced Concrete

In real life,buildings are inevitably affected by static and dynamic loads.However,the low tensile strength,high brittleness and easy cracking of concrete limit its development.In order to improve the mechanical properties of concrete,overcome its brittle failure and enhance its tensile strength,toughness and impact resistance,this paper adopts the method of volume mixing to add short-cut carbon fibers into concrete and carries out static and dynamic mechanical research on it.（1）Using the method of external dispersant,the dispersion effect of carbon fibers in water solution and concrete is investigated.The dispersion effects of cellulose-based dispersant and polyacrylic acid-based dispersant on short-cut carbon fibers with different lengths in water solution and concrete are compared and analyzed.The image processing technology is innovatively used to quantitatively analyze the dispersion of carbon fibers,explore the dispersion mechanism of dispersant,and reveal the internal connection between the dispersion properties of dispersant and the dispersion effect.（2）Based on the research of carbon fiber dispersion,the effects of carbon fiber,PAAS and polycarboxylic acid water reducer on the fluidity of carbon fiber reinforced concrete are investigated,and a calculation formula for carbon fiber reinforced concrete based on the experimental conditions in this paper is proposed.（3）An investigation was conducted on the effect of carbon fiber incorporation on the enhancement of concrete by examining the compressive strength and splitting tensile strength of concrete.The results showed that the compressive strength increased initially and then decreased,with a peak at 0.4%dosage,representing a 22.52%increase in strength compared to plain concrete.The growth rate of splitting tensile strength also exhibited an initial increase followed by a decrease,with a peak at 0.8%dosage,representing a 67.88%increase compared to plain concrete.（4）The bending toughness of carbon fiber concrete is evaluated in terms of failure morphology,bending toughness index,bending toughness ratio and residual bending strength.The results show that when the carbon fiber content reaches 0.8%,the peak load reaches its maximum and the bending toughness ratio is the largest.When the fiber content is 1.4%,the improvement effect on the bending toughness of concrete is optimal.（5）The double-parameter Weibull distribution model is used to statistically analyze the initial cracking impact times N₁and final cracking impact times N₂of carbon fiber reinforced concrete,and compare the impact times of carbon fibers under different fiber volume contents V_Cand failure probabilities P.（6）Analyze and evaluate the drop hammer impact test in terms of impact energy consumption,impact toughness ratio,and post-initial crack impact performance enhancement rate_.Analyze and evaluate the Hopkinson bar impact test in terms of strain rate effect,average failure strength,and dynamic deformation failure.Further determine the impact resistance of carbon fiber concrete and the optimal dosage of 0.8%.