| A large number of waste rubber tires as the product of the rapid development in the peace era,they have already aroused people’s attention.The Waste tire rubber powder mixing in the concrete not only can improve the toughness,frost resistance,shrinkage,anti-fatigue and impact resistance,but also solve the increasingly serious problem of waste treatment,which has profound significance and gradually gained the attention of the vast number of scientific research workers worldwide.But the rubber powder can obviously reduce the strength of concrete because of its physical and chemical properties.How to reasonably add the rubber powder to ensure the strength of the concrete,so that we can use its excellent performance in the practical engineering,it must be dealt with certain after the scientific test and theoretical analysis on the basis of the full study of its working principle,this is the goal of the present article.In this paper,the non-ionic surfactant Division 40(SIPAN40)is utilized under the unitary modification and two-time modification system.Anionic Surfactant 12 alkyl benzene sulfonic acid sodium(SDBD),cationic surfactant two chloride cyanuric acid sodium(SD)and 3 concentrations of alkali solution NaOH to the Waste tire rubber powder Modified treatment,using scanning electron microscope(SEM),Fourier infrared Spectrometer(FTIR),Liquid-Solid interface video contact angle analyzer and particle size analyzer for the micro-characterization of rubber particles before and after modification,and using mathermatic modeling method to characterize the specific surface area of sand-rubber powder mixture.Based on this,the author used a variety of mixed quantities and particle sizes of rubber particles according to different test designs to make cement sand,cement mortar,concrete specimens,test the flexural strength,compressive strength,uniaxial compressive stress-strain curves,combined with mortar performance,the study of the new mixing mortar to 3d,7d,and the early development process of 14d and 28d test blocks subjected to strength,combined with orthogonal test analysis and constitutive model,the paper analyzed the influence mechanism of rubber powder modification,dosage and particle diameter of 3 factors.The above studies suggest that:1.Surface modification can reduce the contact angle of rubber powder and water in different degrees,enhance the hydrophilicity of rubber powder,improve the fluidity of cement-based composites,and improve the performance of its work.This paper proposes a two modified rubber powder system,using the mathematical method of multivariate regression,and carries out a thorough study on the mechanism of two-time modification from microcosmic angle:(1)NaOH solution can dispel the impurities on the surface of the rubber powder to make it smoother,but excessive NaOH is unfavorable to the improvement of its hydrophilicity,which is a kind of effect similar to the physical effect;surfactants can introduce oxygen-containing functional groups on the surface of rubber powders and enhance hydrophilicity,which is a more obvious effect of chemical effect.(2)Two-time modification effect is not added to the single modification.The above two ways can reduce the surface impurities of the rubber powder to enhance the hydrophilic energy than the surface modifier of the oxygen functional group of the introduction.This paper provides a theoretical basis for the exploration of rubber powder modification method,and provides a basis for the application of rubber powder modified concrete.2.Using linear regression method,and by the virtue of the modified rubber powder cement mortar and sand mixture ratio strictly consistent premise,it revealed the cement slurry mobility and sink degree between the close relationship between the existence of consistent with the ratio of the conditions.Liquidity and mechanical properties are also interrelated.3.The effect of different dosage and different sizes of rubber powders on cement mortar varies with the aging period,according to the qualitative and quantitative comparison of the actual water-glue ratio and actual specific surface area of the rubber powder cement mortar,the large diameter rubber powder cement mortar hardening speed is faster than the small diameter rubber particles,and the strength of hardening is smaller than the small diameter rubber powder cement mortar conclusion.4.The amount of rubber powder and particle size has an effect on fine aggregate particle gradation and fine aggregate specific surface area.By using the orthogonal analysis method of the pole difference,the paper reveals the influence of the rubber powder surface modification,dosage and particle size on the rubber powder modified cement-based composites and the mechanism of the early strength of the new mixing mortar to the 28d after forming.5.This paper adopts the classical concrete constitutive equation to convert the uniaxial compressive stress-strain curves of the rubber powder concrete and obtains the constitutive parameters A and B.The paper reveals the effect mechanism of the rubber powder modifiation factor,the admixture quantity factor and the particle diameter factor on the concrete peak stress,and gives the definite physical meaning of A and B.6.The correction model of the rubber powder test contact angle was put forward,and the calculation model of sand-rubber powder fine aggregate specific surface area was established,and the research precision of the rubber powder cement-based composites was increased.Moreover,the theoretical basis was provided for the study on the mechanism of rubber powder concrete from microcosmic angle.7.It is recommended that treating rubber powder with 5%concentration of NaOH solution and the secondary modification of Sipan40 are simple and practical in the modification process,and the mechanical performance enhancement is better than the other surface modification effect. |
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