Improved method for determining optimum compaction temperature of polymer modified asphalt mixtures

Abstract

The invention discloses an improved method for determining optimum compaction temperature of polymer modified asphalt mixtures. The method comprises the following steps: 1, determining a viscosity-temperature curve of asphalt at the shear rate of 25 s<-1>; 2, determining the initial compaction temperature according to the shear rate of 0.52 Pa.s; 3, designing the mix proportion of the modified asphalt mixtures under the initial compaction temperature; 4, selecting three target compaction temperature molding asphalt mixture specimens according to the shear rate of 0.38-0.75 Pa.s, selecting a quadratic function to carry out fitting on concave trends of compaction energy indexes along changes of the compaction temperature, and determining the optimum compaction temperature which is corresponding to the minimum value of a fitting curve; 5, molding the asphalt mixture specimens at the optimum compaction temperature to verify whether the difference value of the void ratio at the initial compaction temperature and the void ratio at the optimum compaction temperature is less than or equal to 0.10% or not. The improved method for determining the optimum compaction temperature of the polymer modified asphalt mixtures disclosed by the invention has the characteristics of clear theoretical basis, easily measured technical indexes, accurate and reliable test results and the like.

Description

Technical field [0001] The invention belongs to the field of road engineering, and relates to an improved method for determining the compaction temperature, in particular to an improved method for determining the optimal compaction temperature of a polymer modified asphalt mixture. Background technique [0002] In the process of asphalt mixture compaction, the friction between the aggregates first decreases and then increases with the increase of compaction temperature, and there is an optimal compaction temperature. At this compaction temperature, the friction between the aggregates is the smallest, the compaction work required during the compaction process tends to be a minimum, and the density of the asphalt mixture specimen tends to be a maximum (see [Sefidmazgi NR, Teymourpour P,Bahia H U.Effect of particle mobility on aggregate structureformation in asphalt mixtures[J].Road Mater Pavement,2013(Sup2):16-34.]). This temperature is defined as the optimal compaction temperatur...

AI Technical Summary

Problems solved by technology

The core technical parameters such as initial compaction temperature and target compaction temperature in the quadratic function fitting method are derived from human experience. In order to obtain the best compaction temperature in one test, it is often necessary to select five or more target compaction temperatures , increasing the workload of the test

In addition, in the quadratic function fitting method, there is no error control link, and the difference between the initial compaction temperature and the estimated value of the optimal compaction temperature cannot be controlled, resulting in the determination of the optimal compaction temperature of the polymer modified asphalt mixture There is a large error

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