1、Designation:D670314Standard Test Method forAutomated Heithaus Titrimetry1This standard is issued under the fixed designation D6703;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indi
2、cates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes a procedure for quantifyingthree Heithaus compatibility parameters that quantify thecolloidal stability of asphalts and asphalt cross blen
3、ds and agedasphalts.1.2 UnitsThe values stated in SI units are to be regardedas standard.No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this stand
4、ard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D8 Terminology Relating to Materials for Roads and Pave-mentsD3279 Test Method forn-Heptane InsolublesD4124 Test Method for Sepa
5、ration of Asphalt into FourFractionsD5546 Test Method for Solubility of Asphalt Binders inToluene by CentrifugeE169 Practices for General Techniques of Ultraviolet-VisibleQuantitative Analysis3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 asphaltene peptizability,nthe tendency
6、 of as-phaltenes to exist as a stable dispersion in a maltene solvent,measured by the Heithaus parameter pa.3.1.2 asphalt state of peptization,na measure of theability of the combination of a maltene solvent and dispersedasphaltenes to form a stable dispersed system.3.1.3 colloidal suspension,nan in
7、timate mixture of twosubstances,one of which,called the dispersed phase(orcolloid),is uniformly distributed in a finely divided statethrough the second substance,called the dispersion medium(ordispersing medium).3.1.4 compatibility,nthe state of peptization of an asphalt,which is measured quantitati
8、vely by the Heithaus parameter P.3.1.5 dispersed phase,none phase of a dispersion consist-ing of particles or droplets of one substance distributed througha second phase.3.1.6 dispersing medium,none phase of a dispersion thatdistributes particles or droplets of another substance,thedisperse phase.3.
9、1.7 flocculation,nthe process of aggregation and coales-cence into a flocculent mass.3.1.8 Heithaus compatibility parameters,nthree param-eters:asphaltene peptizability(pa),maltene peptizing power(po),and asphalt state of peptization(P),measured usingHeithaus titration methods.3.1.9 maltene peptizin
10、g power,nthe ability of a maltenesolvent to disperse asphaltenes,measured by the Heithausparameter po.4.Summary of Test Method4.1 Three 40 mL reaction vials are tared(Fig.1).Threesamples of asphalt of weights 0.400 g,0.600 g and 0.800 g aretransferred to each of three reaction vials.Toluene(3.000 mL
11、)is added to each reaction vial to dissolve the asphalt constitut-ing three solutions which differ by concentration.Each solutionis titrated with isooctane(2,2,4-trimethyl pentane)to promoteonset of flocculation of the solution.4.2 Titrations are performed by placing reaction vials sepa-rately in th
12、e apparatus illustrated in Fig.2.Each reaction vialis separately placed into a 250 mL water-jacketed reactionvessel.A sample circulation loop is made by pumping thesolution through a short path length quartz flow cell housed inan ultraviolet-visible spectrophotometer then back to the reac-tion vial
13、with high flow rate metering pump.A titration loop ismade by pumping titrant into the sample reaction vial at aconstant flow rate using a low flow rate metering pump,thus asecond reaction vessel containing titrant is placed into a second250 mL water-jacketed reaction vessel.During a titration the1Th
14、is test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.47 onMiscellaneous Asphalt Tests.Current edition approved June 1,2014.Published July 2014.Originally approvedin 2001.Last previous edition approved in 2013
15、as D6703 13.DOI:10.1520/D6703-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100
16、Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 output signal from a spectrophotometer is recorded using a dataacquisition system(computer)to record the change in percenttransmittance%T of detected radiation at 740 nm plotted as afunction of time t(Fig.3),as the titrated solution passesthrough a quartz flow cell.4.3 The spectrophotometer output signal measures turbidityof the sample solution as a titration experiment proceeds to aflocculation onset point,correspondin
