Studies On The Properties Of Epoxy Asphalt/Nanoclay Compopsites

In China, epoxy asphalts (EA) have been widely used on the pavement of orthotropic steel bridge decks since 2000. In the first part of this thesis, the enhanced effects of natural fibrous attapulgite (ATT) in warm-mix epoxy asphalt binder (WEAB)/ATT nanocomposites were figured out through a comparison of the properties of the composites with a series of various nanoclay loadings. The rheological, glass transition, thermal stability, mechanical properties, and morphology of WEAB/ATT composites were characterized by rotational viscosity (RV) tests, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), tensile tests, and scanning electron microscopy (SEM). Furthermore, the low-temperature flexibility of WEAB/ATT concretes was investigated by three-point bending beam tests. The test results show that the addition of ATT has no significant effect on the rotational viscosity of WEAB in the initial stage of cure reaction. In addition, the WEAB/ATT composites have better performance than the neat one in thermal stability with higher glass transformation temperature. The tensile strength and elongation at break of WEAB/ATT composites at a loading of 0.5 wt% ATT are 21% and 22% higher than those of the neat WEAB separately. The addition of ATTs also enhances the low-temperature flexibility of WEAB concretes.Secondly, a series of cold-mix epoxy asphalt binder (CEAB)/organic montmorillonite (OMMT) composites were prepared. The effects of OMMT on the structure, glass transition, damping properties, thermal stability, mechanical properties and morphology of CEAB were characterized by XRD, DMA, TGA, tensile tests and SEM. XRD results indicate that epoxy chains intercalated into the OMMT layers and led to the expansion of OMMT layer spacing. The presence of OMMT increases the glass transformation temperature, crosslink density of the neat CEAB. Furthermore, the incorporation of OMMT improves the thermal stability of the CEAB. The CEAB/OMMT composites show higher tensile strength than the neat CEAB. Homogenous dispersion of OMMT in CEAB matrix is observed.Thirdly, the asphalts with different penetration and content were uesd to prepare the high-mix epoxy asphalt adhesive (HEAA). The rotational visicoty, thermal stability, tensile properties and adhesive properties of HEAA were characterized by RV, TGA, tensile tests and lap shear tests. Given all properties of HEAA, the best proportion of HEAA with 36 wt% AH-50 base asphalt was determined.Finally, a series of HEAA/ATT and HEAA/montmorillonite (MMT) composites with different nanoclay loadings were prepared based on the test results of the third part. XRD, RV, TGA, tensile tests, lap shear tests and SEM were carried out to investigate the rheological, thermal stability, tensile properties, adhesive properties and morphology of HEAA/ATT and HEAA/MMT. The test results show thermal stability, tensile strength and adhesive properties of the HEAA/ATT and HEAA/MMT composites increase by the addition of nanoclay. Moreover, nanoclay has a significant effect on decreasing the rotational viscosity of HEAA. SEM observation indicates that nanoclay in HEAA was homogenous dispersion at lower loading and agglomerate at higher loading.