The Research On Performance Of Composite Fiber Asphalt Glue And Its Application In SMA-13

The addition of fibers in SMA has become a common means to improve the pavement performance of asphalt pavements,but most of them are single fibers,and there are few studies on composite fibers.Modern glue theory believes that the composition of the asphalt glue determines the high temperature stability and low temperature deformation ability of the asphalt mixture.The US SHRP research results also show that the low-temperature performance of asphalt glue contributes to 87%of the temperature-shrinkage cracks in asphalt mixtures,which indicates that asphalt glue are the fundamental factors affecting the viscoelasticity of asphalt mixtures.Therefore,it is very necessary to study the performance of fiber asphalt glue.In this paper,the rheological properties of asphalt glue and the road performance of SMA-13 after simultaneous addition of different ratios of mineral wool fibers and granular lignin fibers were studied and compared with the single fiber blends.First of all,based on the initial set of SMA-13 asphalt mixture ratios of 1.5?1.6and 1.7,conventional performance tests such as taper penetration,softening point,and ductility were performed for three types of asphalt mortars.The analysis shows that asphalt glue has better conventional performance when the ratio of powder to glue is 1.6.On the basis of this,seven blending methods of mineral wool fiber and lignin fiber in mass ratio of 0:100?20:80?40:60?50:50?60:40?80:20?100:0 were proposed;The preparation steps of the composite fiber asphalt glue were also determined.Secondly,dynamic shear rheological test(DSR)and low temperature bending beam rheological test(BBR)were used to investigate the rheological properties of fiber asphalt glue at high and low temperatures.According to the temperature scanning and frequency scanning test,when the fiber ratio is 50:50,the high-temperature rheological properties of the composite fiber asphalt glue are best;From the BBR,the 50:50 fiber asphalt glue has the worst low temperature rheological properties,but the reduction is not as obvious as compared to the best single lignin fiber asphalt glue.It can be seen that the effect of fiber ratio on the rheological properties of asphalt glue at low temperature is not significantFinally,The Marshall test has determined the gradation of SMA-13 bituminous mixture and the optimum ratio of different fiber ratios,which are 6.15%?6.17%?6.19%?6.21%?6.23%?6.25%and 6.27%,respectively.Based on this,the road performance of composite fiber SMA-13 was studied,It was concluded that when the proportion of mineral wool fiber and granular lignin fiber is 50:50,the high temperature stability and water stability of the composite fiber SMA-13 asphalt mixture are optimized,Compared with the single fiber mixture,it has a large increase,the low-temperature anti-crack performance is slightly reduced but not obvious and still meet the requirements of the specification.Therefore,in this paper,the road performance of SMA-13 is considered to be the best.