摘要
为评价不同老化程度改性沥青再生前后化学组成的变化,揭示改性沥青再生机理,通过傅里叶变换红外光谱(FTIR)、动态剪切流变(DSR)测试等试验方法,研究了不同老化程度改性沥青再生前后流变性能及微观成分的变化.研究结果表明:随着老化程度的增加,改性沥青的复数模量、相位角及蠕变速率均减小,劲度模量增加;FTIR谱图中C=O基团与S=O基团指数明显增大,丁二烯官能团指数含量减少;添加再生剂后,三种官能团指数均回到老化前附近的状态,表明了老化沥青的性能得到了一定的再生重塑.为了揭示再生沥青流变参数与官能团指数的相关性,基于灰熵关联法来计算各影响因素的相关性,计算结果表明:再生沥青化学组分变化对高温流变特性参数影响程度,由大到小的排序依次为羰基、亚砜基、丁二烯;对于低温劲度模量的影响程度,由大到小排序依次为羰基、亚砜基、丁二烯;对于低温蠕变速率的影响程度,由大到小排序依次为丁二烯、亚砜基、羰基.
Abstract
To evaluate the changes in chemical composition of modified asphalt before and after regeneration at different aging levels and reveal the regeneration mechanism of modified asphalt,the changes in rheological properties and microscopic components of modified asphalt before and after regeneration with different aging degrees were studied through experimental methods such as Fourier transform infrared spectroscopy(FTIR)and dynamic shear rheological(DSR)testing.The research results indicate that as the degree of aging increases,the complex modulus,phase angle,and creep rate of modified asphalt decrease,while the stiffness modulus increases,the index of the C=O and S=O groups in the FTIR spectrum significantly increases,while the content of the butadiene functional group index decreases.After adding regenerants,the indices of the three functional groups returned to the state near before aging,indicating that the performance of aged asphalt has been regenerated and reshaped to a certain extent.In order to reveal the correlation between the rheological parameters of recycled asphalt and the functional group index,this article uses the grey entropy correlation method to calculate the correlation of various influencing factors.The calculation results are show:the degree of influence of changes in the chemical composition of recycled asphalt on the high-temperature rheological properties parameters is ranked in descending order:carbonyl,sulfoxide,and butadiene;the degree of influence on the low-temperature stiffness modulus,in descending order,is carbonyl,sulfoxide,and butadiene;the degree of influence on low-temperature creep rate,in descending order,is butadiene,sulfoxide group,and carbonyl group.
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