Study On Design And Performance Of Chip Seal Using Recycled Rubber Particles As Aggregate

Aggregates are replaced partially by recycled rubber to form chip seal according to the principle of equal volume which realize the recycling of wasted tires and reduce the consumption of natural stones.In this study,XRD test,Zeta potential test,AIMS test and SEM test were carried out to characterize the properties of material.Emulsion moisture content test,contact angle test and Vialit test were carried out for optimizing materials.The optimal design method was chosen by analyzing embedding depth,aggregate dropout and residual aggregate areas.The performance of chip seal using recycled rubber particles as aggregate was evaluated by sweep test,sand patch test,British Pendulum Test and SPSS Statistics software was used for factors correlation analysis.To explore the anti-flaking performance of chip seal using recycled rubber particles as aggregate,the specimens subjected to water and temperature were examined by MMLS3(third Scale Model Mobile Loading Simulator)which can simulate road traffic load.The main results show that:In the process of materials selection,the texture of cryogenic recycled rubber is better than that of the ambient recycled rubber according to SEM and AIMS tests.Considering the product process,the ambient recycled rubber was selected for subsequent study.PCR and limestone combination shows excellent adhesion performance according to contact angle test and Vialit test,thence PCR and limestone combination was selected ultimately for subsequent study.Unit amount of asphalt and aggregate were calculated for chip seal preparation referred to McLeod Design,Modified Kearby Design and Shaanxi Standard.Results of embedding depth,aggregate dropout and residual aggregate areas show:The specimens referred to Shaanxi Standard present the highest embedding depth and the largest residual aggregate area,and the least aggregate dropout rate.Therefore,the unit amount of asphalt(2.23kg/m2)and aggregate(7.91kg/m2)were used for subsequent study.Pre-coating rubber particles with 1.5wt%(equal to the mass of limestone being same volume with rubber particles)hot asphalt is an effective way to decrease aggregate dropout,and barely impacts on surface texture of chip seal.With the increase of aggregate size and the amount of rubber particles,aggregate dropout and mean texture depth raised.And the outcomes of SPSS analysis also explain that the size of aggregate and dropout have notable correlation.As a result,aggregate with a size of 4.75～7.1mm was decided to prepare chip seal for subsequent study.The results of MMLS3 test show that:aggregate dropout rate increased initially,followed by a decrease with the growth of time.Low temperature is a significant factor affecting anti-flaking performance of chip seal.And water-temperature coupling will aggravate the dropout.Overall,when the content of rubber particles does not exceed 50vol%,the rate of dropout increased no more than three percentage points compared with no rubber particles added.It is recommended that the volume replacement rate of rubber particles should not exceed 50%.Chip seal using recycled rubber particles as aggregate shows can realize a large number of recycling and utilization of wasted tires.It is considered that the structure has great engineering application potential and environmental protection value.