Research Of Backcalculated Modulus Correction Coefficient For Asphalt Pavement Based On FWD

With the increasing application of falling weight deflectometer, the backanalysis problem of pavement structure layer modulous has been an critical technology to evaluate the structural performance of pavement. At present, scholars both abroad and at home have performed deep researches on backanalysis of structure layer modulus based on FWD test. Scholars discovered that the modulu from deflection basin backcalculated was unequal to the modulus tested in laboratory, for these difference between the two modulus, backcalculated modulus correction coefficient shuold be established in order to evaluate the structural performance of pavement accurately by FWD test.This dissertation supported by the of traffic construction and science projects for west from ministry of transport:esearch on design method of asphalt pavement structures based on multiple-target, on the base of done FWD test on pavement with different structure, dynamic modulus test for different materials and compare and analysis the results, Then established backcalculated modulus correction coefficient. Chang-shen freeway and Jing-Jin-Tang freeway engineering proved the conclusion.For the selection of backcalculation software, SIDMOD is available by compare the backcalculated result; the law and main infuential factor had been summarized by long-term FWD test for test sections and backcalculation; got the dynamic modulus of asphalt concrete and cement stabilized crushed stone by SPT test, got the resilient modulus of granular material by pick up from experience value and estimate resilient modulus for subgrade soils by physical parameters. Then obtain the correction coefficient by compare the two modulus.For the temperature susceptibility of asphalt concrete, the backcalculated modulus correction coefficients are equation contain T for transform the backcalculated results to modulus test in laboratory, the correction coefficients for cement stabilized crushed stone, granular material, subgrade soils are 0.85, 0.59~0.76, 0.34~0.48.Chang-shen freeway and Jing-Jin-Tang freeway engineering proved the compare conclusion, and the backcalculated modulus correction coefficient are availabe when there are no damage evidently.