1.1 ,This test method covers the determination of bitumen content in materials containing at least 25 ,% bitumen. Bitumen content may usually be expeditiously and accurately determined by Procedure No. 1, Section 7. However, some bituminous materials containing finely divided mineral matter may clog the filter or the mineral residue may not be easily retained, in which cases Procedure No. 2, Section 8, shall be followed.