The Preparation Of Montmorillonite Asphalt Modifier And Mechanism Research

Montmorillonite(MMT)is the most widely studied mineral filler asphalt modifier,which can enhance the high and low temperature performance and anti-aging properties of asphalt.The unique lamellar structure of MMT could be enlarged by surfactant.Use of MMT interlayer characteristics could be modified by structural modulation.The road performance of asphalt could further enhance after mixing with modified MMT.This paper is based on organic and inorganic modification methods.The organic modification of MMT was firstly performed using cetyltrimethyl ammonium bromide(CTAB)to prepare organic bentonite(OMMT).Secondly,the nano-TiO2 pillared montmorillonite(T/M)was prepared by inorganic modification of MMT with butyl titanate.Finally,using of Cu,Ce,Fe metal ions combined with OMMT,we have prepared Cu-doped nano-TiO2 pillared montmorillonite(Cu-T/M)and Ce-doped nano-TiO2 pillared montmorillonite.(Ce-T/M),Fe-doped nano-TiO2 pillared montmorillonite(Fe-T/M).According to relevant test specifications and standards,the organic and inorganic modification and doping modification test methods of bentonite were discussed.We use X-ray diffraction(XRD),scanning electron microscopy(SEM),fourier transform infrared spectroscopy(FT-IR),thermogravimetry-differential thermal analysis(TG-DTA),UV-vis spectrophotometry characterized the chemical structure and microstructure of OMMT,T/M,Cu-T/M,Ce-T/M,Fe-T/M and modified asphalt.The physical properties,high and low temperature performance of different contents modified asphalts are characterized by physical performance test,dynamic shear rheometer(DSR)and low temperature bending rheometer(BBR)tests.The short-term aging,long-term aging,and ultraviolet(UV)aging resistance properties of asphalt are also evaluated by thin film oven test(TFOT),pressure aging vessel(PAV),UV aging test.The photocatalytic performance of T/M,Cu-T/M,Ce-T/M,Fe-T/M modified asphalt was studied using a self-made environmental detection box.The main findings are as follows:(1)The chemical structure and microscopic characteristics of OMMT were characterized by XRD,SEM,FT-IR and TG-DTA.The results showed that CTAB was successfully entered into OMMT.Expanded spacing of OMMT have a good thermal stability and compatibility with polymers.OMMT forms exfoliated structure in asphalt,which can significantly improve the high and low temperature rheological,anti-aging properties of asphalt.The best content range is 4-6%.(2)The results of XRD analysis of T/M show that the anatase TiO2 is synthesized.After adding T/M to the asphalt,modified asphalt high temperature viscoelasticity can be improved.It showed excellent UV aging resistance.The properties of T/M modified asphalt samples have significantly improved under a certain content of 5%.In simulated environmental degradation test of exhaust,increasing illumination intensity and T/M content can increase the degradation rate of NO,CO and HC.(3)The test of XRD shows that the characteristic peaks corresponding to Cu,Fe and Ce ions can be seen in Cu-T/M,Fe-T/M and Ce-T/M.The high temperature rheological properties and anti-UV aging properties of the three kinds of doped pillared montmorillonite are higher than that of T/M modified asphalt.The performance of Ce-T/M modified asphalt is btter than Cu-T/M,Fe-T/M modified asphalt.Under the UV light intensity is 10.4w/m2 and the mixing rate is 6%,the simulation of the NO and HC gas degradation rate of the Cu-T/M>Ce-T/M>Fe-T/M>T/M in vehicle exhaust environment maximum.This result proved that using metal doping can enhance the ability of TiO2 photocatalytic degradation.