Study And Application Of Tunnel Pavement Warm Mix Asphalt Wearing Course

Due to the particularity of tunnel pavement’s environment and employmentconditions, it’s inappropriate to use the conventional hot mix asphalt mixture to pavetunnels. Based on the construction of the right tunnel of Tiger-shaped MountainTunnel in Chen-Ning (from Chen-zhou to Ning-yuan) Expressway adopting warm mixNovaChip Type C Type asphalt mixture, this thesis aims to analyze the effect of thismaterial on the wearing layer of tunnels.By way of the experimental study on the pavement performances and structuraldesign parameters of the two kinds of warm mix asphalt (DAT and Sasobit) formedat different compaction temperatures, a comparison has been made between thepavement performances of hot mix asphalt and warm mix asphalt, and a systematicexposition is made to illustrate the influence of compaction temperatures on theperformances of the two types of warm mix asphalt, thus providing some references tothe application of NovaChip Type C on the wearing layer.The following conclusions are drawn from the repetitive experiments anddetections of the tunnel construction:(1) being high-temperature stability, moisturesensitive and low-temperature cracking resistant, warm mix NovaChip Type Casphalt meets the requirements of the technical specifications when the compactiontemperature is between135℃and165℃and the cooling effect of the two warm mixagents can be dramatically, that is, the temperature will drop30℃; the pavementperformances of warm mix asphalt at the compaction temperature of135℃isapproximately the same as that of hot mix asphalt at the compaction temperature of165℃, the high-temperature stability of warm mix asphalt is better than that of hotmix asphalt, the moisture sensitivity of the former decreases a little, and thelow-temperature cracking resistance of it dose not change significantly.(2) with thecompaction temperature increased from135℃to165℃, the high-temperaturestability of warm mix NovaChip Type C asphalt increases obviously, while themoisture sensitivity does not change apparently, both showing a tendency of increaseat first and decrease later on; the low-temperature cracking resistance has beenenhanced with a tendency of decrease firstly and increase later on.(3) with thecompaction temperature increased from135℃to165℃, the splitting tensilestrengthening ability and the compressive modulus of warm mix NovaChip Type C asphalt has changed little, both showing a tendency of increase firstly and decreaselater on.(4) with the application of warm mix asphalt, the emission of CO2, SO2, CO,NOXand dust have been reduced during the tunnel pavement obviously; with theadoption of NovaChip Type C asphalt mixture with large pores, the traffic noise ofthe tunnel on the experimental section has been reduced by4~8dbs, having aremarkable noise reduction effect.