Determining the Effect of Ageing of Nano-Clay Modified Bitumen Using Atomic Force Microscopy

Abstract

This study investigates the effects of ageing simulation on the physical properties of nano-clay modified bitumens (NCMBs). Bitumen with penetration grade 60/70 is modified with 0, 2 and 4% nano-clay, and the consistency of the samples is characterized using the penetration, softening point, and viscosity tests before and after aging. Atomic force microscopy (AFM) is used to evaluate the surface roughness and tip deflection of the modified bitumens. The results of the consistency tests revealed that the incorporation of nano-clay up to 4% NC resulted in increased hardness of the modified bitumen, and all modified bitumens were affected by ageing; the results for surface roughness and tip deflection showed a similar trend and 2NCMB exhibited the lowest roughness and highest tip deflection. However, the results of consistency tests and AFM for ageing sensitivity of the bitumens are different, indicating that the addition of nano-clay has an effect on the modified bitumen but not on the unmodified bitumen. There is a high correlation between the results of consistency tests, surface roughness and tip deflection, which implies that AFM is able to identify any changes in the fluidity of the bitumen. However, the correlation between tip deflection and penetration is very weak.

Tribological and morphological properties of bentonite nano‐clay/CaCO3 reinforced high‐density polyethylene nanocomposites

“…It is observed from the FESEM micrograph that nano clay powders appear as grains located close to each other (Figure 2A). The appearance confirms the compatibility of nano clay particles with the HDPE matrix due to the consistency with the results presented in the study of Omar et al 16 Whereas CaCO 3 powders have an irregular shape with cleavages around the boundary of the particles and the HDPE (Figure 2B). Similar descriptions of CaCO 3 particles are given in the study of Minkowicz et al 17 CaCO 3 used together with the nano clay powder showed enhanced compatibility resulting in a high stress transfer from the matrix to the particles.…”

“…These deep grooves are identical in appearance and can be seen appearing at different locations on the surface profile (Figure 3C). 16 The excessive wear debris in the form transfer film of the non‐hybrid samples is the result of this exfoliation process on the surface of the wear track. Reflecting on the values of COF, the damage due to dry sliding is further avoided by the transfer film, which is manifested by the decrease in coefficient of friction (C.O.F.)…”

State of the Art Review of Ageing of Bituminous Binders and Asphalt Mixtures: Ageing Simulation Techniques, Ageing Inhibitors and the Relationship between Simulated Ageing and Field Ageing

“…In another AFM study on adhesive surface characteristics, Lyne et al [97] concluded that a correlation existed between elastic modulus, adhesion forces and morphology of bitumen. In similar research, Omar et al [98] investigated the effect of nano-clay as a bitumen modifier and its effect on bitumen ageing behaviour using AFM. It was concluded that AFM has the ability to identify changes in bitumen fluidity, and different bee-like structures were recorded in different bitumen samples, even though they all had the same penetration value.…”

Investigating the influence of chromium layer thickness on thermal stability, adhesion and agglomeration of Cr/Ag/Cr sandwich layers in microelectromechanical systems (MEMS)

“…Their findings indicate that the elevated transfer coefficient observed in the TiO 2 /Ag (Cr)/TiO 2 film resulted from a reduction in the thickness of the silver layers. This reduction led to diminished optical properties, surface plasma effects, and electron scattering, contributing to lower electrical resistance [22]. Fukuda et al employed Al/Ag/Al sandwich layers to enhance the thermal stability of silver films.…”