Research On Geological Radar Diagnosis Technology Of Asphalt Concrete Pavement Disease

There are many bridges appearing the disease before service Life. Because thenumber of bridges increases sharply with the rapid development of road transport. Inthe same time, the problems stand out about the construction quality control and latermaintenance of the bridges. The bridge deck pavement disease is one of the commondiseases on the bridges. It can cause the steel corrosion of the girder, the concreteabscisic and other diseases. This can affect the durability of the bridge structure andbring about traffic accidents and a lot of economic losses. The water damage is acommon break-formed for the common asphalt concrete bridge deck pavement,resulting in deck pavement off, cracks. The main reason is the excessive porosity,density and compaction below standard, which can lead to eventually the destructionof the bridge deck pavement because of the infiltration of the rain water. So the rapid,simple and effective detection methods need to be improved because the traditionaltesting methods can not meet the current bridge deck pavement disease detection dueto the reason of the low efficiency, poor security, and randomness. Ground penetratingradar (GPR) has many advantages such as fast, convenient, non-destructive and so on.It is usually used for subgrade structure layer thickness, substrate thickness of tunnellining cavity to directly identify the disease detection, and rarely used to detectdiseases of deck pavement, especially the control of which can’t directly identify thecompaction index. So this paper will introduce radar to detect diseases of bridge deckpavement, research on reliability of detecting the porosity, density and compactiondegree of the asphalt concrete bridge deck pavement by radar, the main work includesthe following aspects:○1Through experiment method to study the applicability of classical mixeddielectric model to asphalt concrete materials, and do some correction to the classicalmixed dielectric model, put forward the mixed dielectric model which can be appliedto asphalt concrete material.○2Usingthismodifiedasphaltconcretemixingdielectricmodel,putforwardtheformula of relation between asphalt concrete permittivity and void ratio, and reveal theinternal relationship between the dielectric constant with density and compaction of theasphalt concrete.○3To design and carry out the experiment to detect the porosity, density andcompaction degree of the bridge deck pavement by radar. Based on the test results, it proves the rationality of applicability and assumption of voidage expression, themaximum error of the formula to calculate the porosity and the measured value is14.2%, the average error is7.2%; and using numerical methods to find out therelationship between asphalt concrete dielectric constant with density and compaction,the related coefficient of the dielectric constant with density and compaction canrespectively reach0.672and0.815, there is a good correlation.○4The compaction indicators are feasible to judge the effect of using the GPRto detect asphalt concrete deck pavement, through the derivation of the formula and thestudies of tests. In the end, the range of application of the GPR was discussed inengineering.