Research On Hydraulic Asphalt Concrete Mix Design Zone Considering Adhesion Between Acid Aggregate And Asphalt

In the process of aggregate selection of hydraulic asphalt concrete,it is normal to select alkali aggregate to meet the adhesion requirement between asphalt and aggregate.While in the engineering practice,suffering the situation that the storage of alkali aggregate is insufficient is inevitable.And it is urgent and useful to study the mix design of hydraulic asphalt concrete using acid aggregate,which mainly consists of adhesion between asphalt and aggregate and the mix design of asphalt concrete,to make it used in engineering practice safely and efficiently.In this paper,a type of anti-stripping agent named silane coupling agent(SCA)was selected to modify the adhesion,and a type of mix design methodology named mix zone was established basing multiple factors theory and nonlinear programming.The main research results are shown as follows:The modified effect,optimal dosage,and mechanism of SCA were evaluated using surface free energy(SFE)and Fourier transform infrared(FTIR)methods in the mesoscopic perspective.And these results were checked from the macroscopic perspective.The results showed that with the increase of SCA,the SFE and FTIR parameters almost increased initially,reached the maximum at 1.0 wt%,and then decreased.This indicates that the SCA can serve as a molecular bridge to improve the adhesive property between acid aggregate and hydraulic asphalt with the optimal dosage of 1.0 wt%.Insufficient SCA could not modify the adhesive property effectively,while excess SCA led to the hydrogen-bond association and SCA depolymerization,resulting in an adverse effect.An asphalt concrete mix design approach,named Mix Zone,was established basing multiple factors theory and nonlinear programming.Considering the interaction of mix design parameters,filler-asphalt ratio,mortar-aggregate ratio,and acid-aggregate content,the response surface methodology(RSM)was selected to design experiments and establish regression models.And using the nonlinear programming method,a zone,which included all the combinations of mix design parameters meeting all the design requirements,was established.The Mix Zone was checked by some engineering practice.This zone can provide a direct reference for the mix design of small and medium-sized engineering as well as supporting the design of large-sized engineering.In conclusion,the study of this paper on the modification of adhesion between asphalt and aggregate and the establishment of asphalt concrete mix design can provide some support for the mix design of hydraulic asphalt concrete using acid aggregate.