Detection and analysis method for rapid delineation of aging stages of styrene-butadiene-styrene modified asphalt

A detection and analysis method for rapid delineation of aging stages of styrene-butadiene-styrene (SBS) modified asphalt, comprising the following steps:

• (1) performing a Fourier transform infrared spectroscopy (FTIR) test on unaged SBS-modified asphalt samples, detecting the absorbance of infrared spectrum characteristic functional groups polystyrene and polybutadiene of unaged SBS-modified asphalt at 699 cm−1 and 966 cm−1, calculating a value of A699/A966, and recording the value as an unaged SBS copolymer index IB0/S0;
• and detecting the absorbance of the unaged SBS-modified asphalt at 1030 cm−1, 1456 cm−1, 1600 cm−1, and 1700 cm−1, calculating functional group indexes of sulfoxide group, aliphatic group, aromatic group and carbonyl of the unaged SBS-modified asphalt, and recording the same as indexes of unaged neat asphalt SI0=A1030/ΣA650˜2000, IB,aI0=A1456/ΣA650˜2000, ARI0=A1600/ΣA650˜2000, and CI0=A1700/ΣA650˜2000;
• A699, A966, A1030, A1456, A1600, and A1700 referring to corresponding peak areas at infrared spectrum wave numbers of 699 cm−1, 966 cm−1, 1030 cm−1, 1456 cm−1, 1600 cm−1, and 1700 cm−1, and ΣA650˜2000 referring to a sum of peak areas at infrared spectrum wave numbers of 650 cm−1−2000 cm−1;
• (2) performing the FTIR test on laboratory-fabricated SBS-modified asphalt samples or in-service SBS-modified asphalt pavement samples;
• detecting the absorbance of the laboratory-fabricated SBS-modified asphalt or in-service SBS-modified asphalt pavement samples at 699 cm−1 and 966 cm−1, calculating a value of A′699/A′966, and recording the value as an aging SBS copolymer index IB/S;
• and detecting the absorbance of the laboratory-fabricated SBS-modified asphalt or in-service SBS-modified asphalt pavement samples at 1030 cm−1, 1456 cm−1, 1600 cm−1, and 1700 cm−1, calculating functional group indexes of sulfoxide group, aliphatic group, aromatic group and carbonyl of the aged SBS-modified asphalt, and recording the same as indexes of aged neat asphalt SI=A′1030/ΣA′650˜2000, IB,aI=A′1456/ΣA′650˜2000, ARI=A′1600/ΣA′650˜2000, and CI=A′1700/ΣA′650˜2000;
• and
• (3) delineating three aging stages of SBS-modified asphalt according to changes of infrared spectrum characteristic functional group indexes obtained by actual detection and calculation:
• a, an SBS polymer swelling stage:
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