The Effect of Ageing on Chemical and Mechanical Properties of Asphalt Mortar

Abstract

Asphalt mortar is a mixture of bitumen, filler, and sand. Mortar plays an important role in asphalt mixtures as it serves as the adhesive between the coarser aggregates. Due to the effect of bitumen ageing, the chemical and mechanical properties of asphalt mortar evolve with time. The mortar becomes more brittle and prone to cracking, thus leading to inferior pavement performance. In this study, Fourier transform infrared (FTIR) spectrometry was used to quantify changes in the chemical functional groups related to ageing and to calculate the carbonyl and sulfoxide indices. In addition, frequency sweep tests and uniaxial tension tests were performed by means of dynamic shear rheometer (DSR) tests to determine evolution of the stiffness and strength due to ageing. Two different oven ageing protocols were used to evaluate the effect of fine mineral particles on bitumen ageing. The protocols differed with respect to the order of ageing and mixing of the constituents. The results showed that both the chemical and mechanical properties of mortars significantly changed with ageing. Specifically, the carbonyl index, stiffness, and strength of the mortar increased. Under the same ageing conditions, a higher ageing level was observed for mortars produced by first mixing and then ageing compared to the mortars produced by mixing aged bitumen with filler and sand. This could be due to the presence of sand and filler particles, which resulted in an increased length of diffusion paths and consequently a slower ageing process.

Analysis of the microcharacteristics of different kinds of asphalt based on different aging conditions

“…As the asphalt binder generated no evident characteristic fingerprint within the wavenumber range of 1800-2400 cm -1 , the absorption peak within this range was not reflected in the spectrum. According to previous research results, the carbonyl index and sulfoxide index were used as evaluation indices of the aging degree of asphalt samples [43][44][45]. The carbonyl index and sulfoxide index can be calculated with Eqs.…”

The Effect of Addition of Antioxidant 1,2-dihydro-2,2,4-trimethyl-quinoline on Characteristics of Crepe Rubber Modified Asphalt in Short Term Aging and Long Term Aging Conditions

“…Furthermore, long-term characterization using FTIR analysis in the range of wavenumbers from 4000 to 600 cm −1 . Long-term asphalt aging is indicated by the formation of carbonyl groups (-C=O) at the wave number 1700 cm −1 and sulfoxide (-S=O) at the wave number 1030-1070 cm −1 [42,43].…”

“…While the group at wave number 1060 cm −1 shows the sulfoxide (S-O) groups of asphalt [42][43][44]. Naturally, asphalt has a sulfoxide group because asphalt contains a certain amount of sulfur.…”

Effect of aging on low-temperature crack resistance and water stability of polyester fiber asphalt mixture

“…Therefore, some scholars analyzed the influence of time and temperature on asphalt aging and found that the longer the aging time and the higher the temperature, the deeper the aging of asphalt and the worse the paving performance of asphalt mixes [23][24][25][26]. At the same time, in order to further understand the aging process of asphalt, it was found through microscopy that aging causes changes in the chemical functional groups of asphalt, which results in the nanomorphology and micromechanical properties of asphalt being affected [27][28][29][30][31].…”