Research On Variability And Control Of Asphalt Concrete Pavement Compaction Degree

In the construction of asphalt concrete pavement,although the compaction ratio of construction costs is not high,its role is very important.Compaction effect provides road pavement with better performance,larger stability and intensity,and longer service life.Early damage phenomenon of pavements in our country is very common,one of the important factors is insufficient compaction.However,variability of concrete compaction inevitably exists in the compaction of pavements,how to control and reduce the degree of compaction variability has become a focus in the study today.In this paper,we started from the basic principle of compaction,and analyzed the internal change of asphalt mixture in the compaction process,described the principle of the role of various mechanical compaction to the mixture from mechanics,provided a theoretical basis for the selection of the compaction process.The article offered a parameter describing the variability of compactness in size--the coefficient of variation Cv,which can reflect the randomness of compaction variation.By combining laboratory tests and practical engineering data,we analyzed the causes of variation of compaction from various aspects.In terms of the asphalt mixture itself,asphalt,mineral composition of these material properties and the amount have a effect on it,gradation and mixture ratio can also affect the degree of formation of compaction.Viewing from the external environment,the mainly factor is temperature of mixture,In addition,due to the temperature,wind speed,solar radiation,the under layer thickness could affect dropdown of the rolling temperature,these factors would cause that the asphalt mixture compaction appears uneven.The rolling machine is the direct reason for the formation of compaction degree,so the selection,combination of compaction machinery and its parameters would affect the compaction degree.Favourable compaction technology can get good compaction effect,and is helpful to reduce the variability of the compaction degree.In order to control the variability of compaction,we can control two indicators:optimal compaction temperature,effective compaction time.Within the scope of the two control targets,we should pay attention to every detail of the compaction construction,choosing reasonable compaction machinery and the compaction process.The practice has proved that only take the indoor Marshall density as a standard to measure compaction can not reflect the condition of the compaction actually,we should take dual controlling method of combining the Marshall density criterion and the maximum theoretical density standard.Through the research of variability and control of the compaction degree,we can improve the compaction quality,the research play a positive role on the pavement's performance enhancement.