| Our construction of the transportation infrastructure is developing sharply. A large number of road tunnel projects have started to be undertaken. The level of pavement for road tunnel is directly related to the driver operator quality and security, but the asphalt pavement, which is the mainstream material to pave the road to bring comfort and security for the drivers, couldn't have popular application in long and enclosed space because the asphalt is easy to get fire itself. At the same time due to the narrow, enclosed and noise space in the tunnel, it is of great practical significance to take researches on (Fire-retarding & Noise-reducing Asphalt Pavement, FNAP)Through the analysis of tunnel paved technique domestic and abroad, we know that using organic fire retarding agent only into fire-retarding asphalt pavement led high toxicity, bad road performance and high cost, meanwhile it couldn't control the technique problem such as gasoline combustion and the noise-reducing performance is not so well. So the author put forward that using the high porosity structured as the dominant for fire-retarding while using the fire-retarding asphalt as the assistant. Using the design of open graded and high porosity structurally which has the function of making the gasoline escaped, asphyxiating combustion and reducing the noise. Using fire-retarding and high viscosity modified asphalt and fire-retarding flour as the material to prepare FNAP, of which the dynamic stability could climb to 8672 times/mm, the Cantabria Loss is 5.23% and it has excellent road performance. In addition, the average sound absorption coefficient is 0.418, better than others such as SMA. And in the miniature fire tests, the gasoline was escaped more than 80%, the temperature was below 200℃on the surface and the temperature of environment was also below 50℃. Its fire-retarding performance is superior to common asphalt pavement and cement concrete pavement, which could satisfy the requirements of comfort and security for the large road tunnel projects.While Adding APP/PER into high viscosity modified asphalt and using colloid mill milling technique to prepare fire-retarding and high viscosity modified asphalt, the viscosity reached 76000Pa·S at 60℃, the ductility was above 60cm at 5℃, the differential education softening point was only 0.6℃, the limiting oxygen index(LOI) was more than 28%, and the fume density was controlled below 50, which get the level of American ANSI/UL-94 V-1. The asphalt not only has excellent road and fire-retarding performance, but also solves the problem of education. Taking ATH as dominant, MH as assistant, Zeolite as acceleration and diatomite as modifier ,the author developed AM-ZD fire-retarding filler which both had fire-retarding and modified function. The LOI of the asphalt adhesive cement was above 30%, and the physical and chemical performance was better than limestone filler, which could improve the road performance effectively.Porous pavement could effectively improve the noise-reducing performance, and the average of sound absorption coefficient was 0.4. Through doing test and analyzing mechanism, the porosity of the noise-reducing pavement should be above 18%. The spot test of Expressway from WuHan to YingShan also shows that porous pavement could absorb the noise efficiently, and the noise-damping level would climb to 4.7dBA. The miniature fire tests validated the good fire-retarding performance of porous pavement. A lot of gasoline was escaped and asphyxiated, which was not concerned with combustion, so the burning time was shorten. The porosity of FNAP should be between 16～20%. Using the design of open graded and porous FNAP or the tunnel surface has excellent performance, so it's necessary to popularize it. |
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