The influence of the most important parameters on the service life of reinforced asphalt overlay with geogrid materials in bending mode was examined by employing the Taguchi method and analysis of variance techniques....The influence of the most important parameters on the service life of reinforced asphalt overlay with geogrid materials in bending mode was examined by employing the Taguchi method and analysis of variance techniques. The objectives of this experiment was to investigate the effects of grid stiffness, tensile strength, coating type, amount of tack coat, overlay thickness, crack width and stiffnesses of asphalt overlay and existing asphalt concrete on propagation of the reflection cracking. Results indicate that the stiffnesses of cracked layer and overlay are the main significant factors that can directly improve the service life of an overlay against the reflection cracking. Generally, glass grid is more effective in reinforced overlay than polyester grid. Effect of crack width of the existing layer is significant when its magnitude increases from 6 to 9 mm.展开更多
A pavement reflectance measurement system is established based on a gonio-photometerexisting by chang- ing a bracket to carry the road sample and luminance meter, adding a collimated light source to provide incident l...A pavement reflectance measurement system is established based on a gonio-photometerexisting by chang- ing a bracket to carry the road sample and luminance meter, adding a collimated light source to provide incident light. This automated system could finish the reflection measurement of a road sample in 4 h. An uncertainty budget of this measurement system is made and the combined standard uncertainty of Q0 is 5.26%.展开更多
One of the main problems with roads and highways in China is the reflection cracking caused by the cement stabilized subbase layers passing through the overlying asphaltic layers. The cracks permit the ingress of mois...One of the main problems with roads and highways in China is the reflection cracking caused by the cement stabilized subbase layers passing through the overlying asphaltic layers. The cracks permit the ingress of moisture which softens the layers below the subbase resulting in loss of support and accelerated breakdown of the subbase layer and reduction in the tiding quality. The aim of this paper is to present the use of South African pavement design approach of deep structure and thin surfacing to overcome the existing problems. The deep pavement structure provides good long-term support and avoids the influence of moisture ingress, which means that only surfacing damage needs to be repaired. An unbound crushed stone base layer which is an integral component of the pavement structure limits reflection cracking. The paper first deals with the South African pavement design procedure and contrast this with the Chinese pavement design method. The inherent weaknesses of these methods are discussed and flowing from this discussion proposals for adapting the South African approach to China is presented. The resultant proposals have a high likelihood of success and will counteract the influences of extreme climate and rampant overloading that occurs on the Chinese roads.展开更多
文摘The influence of the most important parameters on the service life of reinforced asphalt overlay with geogrid materials in bending mode was examined by employing the Taguchi method and analysis of variance techniques. The objectives of this experiment was to investigate the effects of grid stiffness, tensile strength, coating type, amount of tack coat, overlay thickness, crack width and stiffnesses of asphalt overlay and existing asphalt concrete on propagation of the reflection cracking. Results indicate that the stiffnesses of cracked layer and overlay are the main significant factors that can directly improve the service life of an overlay against the reflection cracking. Generally, glass grid is more effective in reinforced overlay than polyester grid. Effect of crack width of the existing layer is significant when its magnitude increases from 6 to 9 mm.
文摘A pavement reflectance measurement system is established based on a gonio-photometerexisting by chang- ing a bracket to carry the road sample and luminance meter, adding a collimated light source to provide incident light. This automated system could finish the reflection measurement of a road sample in 4 h. An uncertainty budget of this measurement system is made and the combined standard uncertainty of Q0 is 5.26%.
文摘One of the main problems with roads and highways in China is the reflection cracking caused by the cement stabilized subbase layers passing through the overlying asphaltic layers. The cracks permit the ingress of moisture which softens the layers below the subbase resulting in loss of support and accelerated breakdown of the subbase layer and reduction in the tiding quality. The aim of this paper is to present the use of South African pavement design approach of deep structure and thin surfacing to overcome the existing problems. The deep pavement structure provides good long-term support and avoids the influence of moisture ingress, which means that only surfacing damage needs to be repaired. An unbound crushed stone base layer which is an integral component of the pavement structure limits reflection cracking. The paper first deals with the South African pavement design procedure and contrast this with the Chinese pavement design method. The inherent weaknesses of these methods are discussed and flowing from this discussion proposals for adapting the South African approach to China is presented. The resultant proposals have a high likelihood of success and will counteract the influences of extreme climate and rampant overloading that occurs on the Chinese roads.
