Application of spectrophotometry on detecting asphalt content of emulsified asphalt

As an environmental friendly technology, emulsified asphalt can effectively reduce the energy consumption and emission during the road construction and has become an effective way to achieve the sustainable development of road engineering. Asphalt content plays an important role in both emulsified asphalt production and acceptance check system. Traditional methods for measuring the solid content of emulsified asphalt were to remove the water in the emulsified asphalt by heating. However, there were many drawbacks for these kinds of methods such as human factors, time consuming and low testing accuracy etc. A potential new technique namely Spectrophotometry was introduced to detect the asphalt content in the emulsion. Two asphalts and three emulsifiers were introduced to preparing the emulsified asphalts with a series of asphalt contents. UV-Vis spectrophotometer and laser particle size distribution analyzer were used to obtain the absorbance and particle size as well as distribution data. Statistical methods and linear regression were used to establish and verify the prediction models between asphalt content and absorbance. Time consumption analysis was preformed to study the simplicity of this method. The results showed that the prediction model of asphalt content and absorbance could be established by measured the absorbance area from 400 nm to 600 nm after diluted 1800 times by water. In addition, the results also illustrated that the asphalt particle size and distribution had great influences on the absorbance of emulsified asphalt. Moreover, it also indicated that emulsifier and hydrochloric acid could be used to improve the accuracy of the prediction model.