Method for quantitatively evaluating new-asphalt and old-asphalt mixing degree based on reclaimed asphalt mortar

A method for quantitively evaluating a blending degree of new- and old-asphalt based on recycled asphalt mortar, comprising the following steps:

• step S1:
• determining use amounts of reclaimed asphalt pavement (RAP), a new aggregate, a new mineral filler, and new asphalt in the recycled asphalt mortar, and contents of an old aggregate, an old mineral filler, and old asphalt in the RAP;
• preparing recycled asphalt mortar with complete blending of the new asphalt and the old asphalt and recycled asphalt mortar with actual blending of the new asphalt and the old asphalt based on the use amounts of the RAP, the new aggregate, the new mineral filler, and the new asphalt, and contents of the old aggregate, the old mineral filler, and the old asphalt in the RAP;
• step S2:
• testing linear viscoelastic areas of the recycled asphalt mortar with complete blending of the new asphalt and the old asphalt and the recycled asphalt mortar with actual blending of the new asphalt and the old asphalt;
• step S3:
• testing viscoelastic parameters of the recycled asphalt mortar with complete blending of the new asphalt and the old asphalt and the recycled asphalt mortar with actual blending of the new asphalt and the old asphalt based on the linear viscoelastic areas in step S2;
• step S4:
• fitting complex modulus main curves of the recycled asphalt mortar with complete blending of the new asphalt and the old asphalt and the recycled asphalt mortar with actual blending of the new asphalt and the old asphalt based on the viscoelastic parameters in step S3, and calculating complex moduli;
• and
• step S5:
• calculating a complex modulus deviation rate and the blending degree of new- and old-asphalt that are at a key frequency based on formulas
• MDI
• =
• 1
• N
• ⁢
• ∑
• i
• -
• 1
• N
• ⁢
• ❘
• "\[LeftBracketingBar]"
• G
• actual
• ⁢
• blending
• ⁡
• (
• f
• i
• )
• *
• -
• G
• complete
• ⁢
• blending
• ⁡
• (
• f
• i
• )
• *
• G
• complete
• ⁢
• blending
• ⁡
• (
• f
• i
• )
• *
• |
• and
• ⁢
• DOB
• =
• 1
• -
• MDI
• ,
• wherein MDI represents the complex modulus deviation rate;
• DOB represents the blending degree of new- and old-asphalt;
• N represents a number of parallel tests;
• G
• actual
• ⁢
• blending
• ⁡
• (
• f
• i
• )
• *
• represents a complex modulus of the recycled asphalt mortar with actual blending of the new asphalt and the old asphalt;
• and
• G
• complete
• ⁢
• blending
• ⁡
• (
• f
• i
• )
• *
• represents a complex modulus of the recycled asphalt mortar with complete blending of the new asphalt and the old asphalt.
• the RAP in the recycled asphalt mortar with actual blending of the new asphalt and the old asphalt is added in a form of RAP mortar composed of the RAP old aggregate, the old asphalt, and the RAP old mineral filler;
• and the RAP mortar is obtained by finely sieving an RAP material with a particle size less than 2.36 mm.
• in step S1, a method for preparing the recycled asphalt mortar with complete blending of the new asphalt and the old asphalt comprises the following steps:
• step A1:
• compounding the old asphalt and the new asphalt in the RAP in the recycled asphalt mortar to obtain completely blended recycled asphalt;
• step A2:
• heating the completely blended recycled asphalt in step A1 at 160° C. for 1 h, and heating the new aggregate, the RAP old aggregate, the RAP old mineral filler, and the new mineral filler at 170° C. for 3 h;
• and
• step A3:
• stirring the new aggregate and the RAP old aggregate in step A2 at 160° C. for 30 s, adding the completely blended recycled asphalt for agitation for 60 s, and adding the RAP old mineral filler and the new mineral filler for agitation for 120 s, wherein an agitation rate is 800 r/min;
• in step S1, a method for preparing the recycled asphalt mortar with actual blending of the new asphalt and the old asphalt comprises the following steps:
• step a1:
• heating the new aggregate at 170° C. for 3 h, heating the RAP mortar at 110° C. for 1 h, and heating the new asphalt at 160° C. until the new asphalt is in a flowing state;
• and
• step a2:
• stirring the new aggregate and the RAP mortar in step a1 for 30 s, adding the new asphalt in step a1 for agitation for 60 s, and adding the new mineral filler for agitation for 120 s, wherein a stirring rate is 800 r/min.