Preparation And Research On The Rheological Characteristics Of Montmorillonite/Asphalt Nano-composites

Asphalt is widely used in road pavement.Unfortunately,ordinary asphalt is a form of liquid at high temperature which can cause high temperature rutting.It has resulted in the necessary to enhance the properties of existing asphalt material.In this paper,the organic modification of Na-montmorillonite(Na-MMT)clay by a reaction with the cetyl trimethyl ammonium bromide(CTAB)was studied for the effects of preparation method,modifying time,reaction temperature and CTAB content on the intergallery distance of the organic montmorillonite(OMMT).And then,montmorillonite/asphalt nanocomposites were prepared by melt blending with OMMT.The effects of different OMMT content,reaction time,modifying temperature and shear speed on the nanocomposites physical properties,such as penetration,softening poin and ductility,were investigated by orthogonal test.At last the rheological characteristics of the composites and the preliminary modification mechanism were investigated.The structures of the montmorillonite were characterized by X-ray diffraction(XRD).The microstructures of examples were analysed by scanning electron microscope(SEM).The thermal decomposition performances of OMMT were studied by thermogravimetry and derivative thermogravimetry(TG-DTG).The chemical structures of silicates were evaluated by Fourier transform infraredspectroscopy(FTIR).The rheological characteristics of composites were studied using the dynamic shear rheometer(DSR).The XRD and FTIR results show that the organic cations have intercalated into the layers to form the intercalated structure.Ultrasonic method can effectively increase the interlayer spacing of montmorillonite from 1.34nm to 3.85nm.The optimum conditions was CTAB content 2.0CEC,reaction temperature 50?,reaction time 4h.The orthogonal experiment indicated that the optimum conditions to prepare montmorillonite/asphalt was OMMT content 5wt%,reaction temperature 150 C,stirring speed 10.0kr/min,reaction time 10min,and the principal factor was the correlation of OMMT content.DSR tests showed that the addition of OMMT increased the rutting factor.As OMMT content more than 5wt%,the composites can be improved 2 PG level at high temperature performance,reaching PG82.The viscosity of bitumen has been improved especially at the temperature below 60?.Sticky temperature relationship was linear in log-log coordinate system as lg?=n-mlgT.Penetration index value showed that the composites were sol-gel structure.