Experimental Study And Analytical Modelling Of Rubber-Modified Asphalt Performance

In Liberia,due to the combined effects of increasing vehicle load and repetitions,changes in ambient temperature,and rainfall,the asphalt pavement layer develops cracks,potholes,loose spalling,and water seepage in the early stage of operation.Therefore,the pavement layers structure design by empirical approaches can no longer meet the service life requirements,and the use of new materials and design methods is of great significance to improve the performance of road pavement in Liberia.Also,a large number of waste rubber tires are disposed of in the country,occupying the land and causing environmental pollution.Hence,taking the Vai Town to Caldwell road section damage as an example,this research experimentally investigates the effect of adding waste rubber particles to asphalt binder to enhance the properties of asphalt mixture by means of the Marshall test method and uses the KENLAYER programming to predict structural performance responses of typical asphalt pavement crosssections,which improves the performance of pavement layer while realizing the recycling of solid waste resources and protecting the environment.The main research contents and achievements are as follows:1)The effect of asphalt content on the properties of dense-graded hot mix asphalt(HMA)was studied.The results showed that 4.8% was found to be the optimum asphalt content(OAC)without affecting the mix design requirement.2)The effect of waste rubber particles on the properties of asphalt mixtures was also studied.The findings revealed that at 180℃ blending and 60℃ testing temperatures,12% by weight of the OAC is recommended as the optimum rubber content(ORC)of the asphalt mixtures.It can be stated that the utilization of rubber particles as a partial replacement of asphalt to improve road surfacing is one of the promising strategies for sustainability.3)The structural responses of typical pavements using the KENLAYER algorithm showed that each pavement cross-section behaves differently due to the effects of various input parameters.It is appropriate to say that the pavement layer thicknesses and material properties can be evaluated by analytical modeling,and the pavement design life is predicted due to the effect of vehicle loads and environmental conditions.The research of this project can provide a meaningful reference for the pavement design of newly built roads in Liberia.The thesis contains 39 figures,19 tables,and 117 references...