Table 1 Examples of FTIR analysis used to study the ageing of bitumen.

Wang et al.⁵

Field aged

Solvent extraction from a core sample, then centrifuge

Lab-based ATR

Area of 1700 cm⁻¹ peak (C=O bonds) normalised by area of 1376 cm⁻¹ peak (C–H bonds)

Wu et al.¹⁵

Field aged

Bitumen recovered from sample core (method not stated)

Lab-based, not stated (ATR?)

Area of peak at 1700 cm⁻¹ normalised by Σ (areas of spectral bands between 4000 and 400 cm⁻¹)

Lamontagne et al.¹⁶

Field aged and heated within custom FTIR oxidation cell

Solvent extraction and evaporation

Transmission through KBr plate

Area under 1753–1635 cm⁻¹, normalised by area under other bands from 2983 to 724 cm⁻¹

Arafat et al.¹³

RTFO and PAV

Solvent extraction and filtering in the field

Hand-held FTIR with ATR probe

Baseline-corrected peak heights at 1695 cm⁻¹ (C=O) normalised by that at 2920 cm⁻¹ (CH₂)

Nivitha et al.¹⁷

RTFO and PAV

Solvent extraction and evaporation

Transmission through thin film on KBr plate

Area under 1768–1725 cm⁻¹, normalised by Σ (area of several bands between 1720 and 715 cm⁻¹)

Hofko et al.¹⁴

RTFO

Direct application of heated bitumen

Lab-based FTIR-ATR

Area under 1666–1746 cm⁻¹ carbonyl region, normalised by region 2923 cm⁻¹ (aliphatic) and referenced to area under region 1319–1520 cm⁻¹ (also aliphatic)

Cheraghian et al.¹⁸

RTFO and UV

Not stated

Lab-based FTIR, transmission

Area under band at 1700 cm⁻¹ normalised by Σ area under bands at 1460 and 1375 cm⁻¹

Porot et al.¹⁹

RTFO and PAV

Not stated

11 lab intercomparison study: 9 used ATR, 2 used transmission

Area under different ranges from 1728 to 1674 cm⁻¹, normalised by CH₂/CH₃ bands area under different ranges from 1510 to 1330 cm⁻¹

Bowden et al.³

RTFO and UV

Close contact with unaltered sample

Lab-based and hand-held DRIFTS

Area under 1755 to 1636 cm⁻¹