Research On The Effect Of Asphalt Components To Environment In The Course Of Using

In recent years, China and the world face serious environmental pollution problems, especially for the organic pollutants, with high toxicity and complexity, it is difficult bring that under control, so organic pollutants become a key and difficult problem in environment monitoring and governance. The components of asphalt can migrate into the environment in the processing and using, which can cause environment pollution, so asphalt is one of the organic pollution sources. In order to evaluate the harmful of asphalt components to environment, this paper studied the harmful of asphalt components to air and water, then by guiding the use of asphalt material to reduce or avoid the harmful of asphalt components to the environment.In evaluation the harmful of asphalt fumes to air, the laboratory asphalt fumes generation system composed mainly by a reactor was used to study the effect of mixing conditions on the asphalt fumes emission and their chemical composition. The results showed that the asphalt fumes were mainly composed by the particles which diameter are larger than 3μm, but the particles which diameter are less than 3μm and the gaseous substances were very small, and the contents were far below the levels of the particles with diameter larger than 3μm. The emission of asphalt fumes increased with the increasing of temperature, time and air volume, but the asphalt fumes under stirring were less than that under no stirring. The composition analysis meaned asphalt fumes were mainly composed by alkane compounds, aromatic compounds and heterocyclic compounds with sulfur, nitrogen or oxygen. With the increase of temperature, time and air volume, the aromatic and heterocyclic compounds increased, but the changing trend of alkane compounds was contrary. Comparing to the stirring, the aromatic compounds and heterocyclic compounds under no stirring were larger, and the ratio of alkane compounds was less. All the results showed that mixing conditions had less effect on the alkane compounds, while on the aromatic compounds and heterocyclic compounds which had more effect. Taking the distribution of asphalt four components as the index in laboratory, the asphalt fumes emissions under mixing conditions was simulated under the basis of influencing factors, then calculation the asphalt fumes emission of nearly a decade, and the results showed the annual emissions of asphalt fumes in recent years were all over 25000 t. In evaluation the harmful of asphalt components to water, the leaching test was taken to study the leachability of asphalt at room temperature first. The results showed that the components could be leached from asphalt and into water, but the contents were very small and below the limit of surface water. However, the study on influencing factors showed that temperature, pH value and chlorate of leachate could effected the leaching of asphalt components, which indicated asphalt component had the potential harmful to water.To evaluate the potentially harmful of asphalt components to water, this paper taked the methods of orthogonal and single factor to get the conditions under which the contents of components leaching from five asphalt were the largest, then quantitative and qualitative analysis were taken to analyse the components leaching from asphalt. Quantitative analysis showed that the COD values of leachate were more than the limited of surface water; and qualitative analysis showed that the components leaching from asphalt mainly composed by the compounds containing hydroxyl and carbonyl which mainly distributed in resin and asphaltene, followed by the alkane compounds. The hazard assessment of components leaching from asphalt showed that the components contained some hazardous compounds priority controlled by environmental, but the quantitative analysis showed that the content was below the instrument detection limit, which indicated the high toxic components leaching from asphalt were very small. The effect of asphalt aged on the leaching of components showed that with he aging of asphalt the content of components leaching from asphalt increased, which indicated the potential harmful of asphalt to water enhanced with the use of asphalt. The study of leaching series indicated that the leachate COD values showed a decreasing trend with the increase in the leaching times, which meaned that as the erosion of rain, the components leaching from asphalt would be less and less, so the potential harmful of asphalt to water decreased with the increase of leaching times.Comparing the harmful of asphalt components to air and water, one kilogram asphalt could released 0.7g of polycyclic aromatic hydrocarbons under the conditions of asphalt mixing; but the content of phthalate was less than the limit of surface water under the maximum leaching condition, all which meaned the harmful of asphalt components to air was larger than the harmful of components to water.In order to reduce the harmful of asphalt fumes to air, this paper studied the asphalt fumes retraining methods. First, the correlation between the kinds of carrier gas and the asphalt fumes emission was studied, as well as the analysis of functional groups and oxygen element content of asphalt, the results showed that asphalt fumes generation mechanism was the oxidation of its components. By examining the inhibitory effect of five free radical inhibitors on A asphalt, a good inhibitor and its content were got. The inhibitory effect of a inhibitor on five asphalt showed that one inhibitor had the same effect on the asphalt from the same crude oil, but it was impossible to find one inhibitor that has good inhibitory effect to all asphalt. For the five asphalt this paper used, a and c inhibitors in dosage of 4% both had the good inhibitory effect to A, C, D and E asphalt, while there was not one inhibitor had good inhibitory effect to B asphalt, even the adding of inhibitors let to an increase in asphalt fumes emission.The effect of inhibitors on the performance of asphalt showed that when the inhibitor had a good inhibitory effect on the asphalt fumes emission, the adding of inhibitor could not affect the performance of asphalt. However, if the inhibitors could not inhibit the emission of asphalt fumes, even lead to the increasing of asphalt fumes emissions, then the inhibitors would affect the performance of asphalt and led the performance of asphalt accession towards the asphalt aging direction.Inhibitors on the effects of performance of TFOT aged asphalt indicated that the adding of inhibitor led to the decrease in the quality changing of asphalt, however they almost not affected the performances of TFOT aged asphalt. The studies on the components structure of asphalt after TFOT aged showed that the adding of c inhibitor lead to the reduction on the strength of caibonyl absorption peak, which showed that the adding of inhibitor inhibited the reaction between the asphalt components and oxygen, which inhibited the oxidation of components, and thus validated its inhibitory effect on the asphalt fumes emission.