AASHTO TP 72:08 (2015) Standard Method of Test for Quantitative Determination of the Percentage of Lime in Hot Mix Asphalt (HMA).
4.1. Atomic Absorption (AA) Spcctromctiy or ion Exchange Chromatographv (IEC).—These methods are able to measure the concentration of chemical elements, in this case calcium, in aqueous solutions. AA Spectrometry measures the intensity of a characteristic color imparted to a flame by the presence of calcium ions in the test solution. IEC measures the change in electrical conductivity of the solution. IEC can identify components of mixtures; AA Spectrornetry can only measure one element at a time.
4.2. Balance—An analytical balance conforming to M 231, Class B.
4.3. heating Device—A small hot plate or other suitable device shall be available for supplying sufficient heat under the flask to bring the solution to a boil. Suitable shields, baffle plates, or sand baths shall be used on the surfaces of the hot plates to minimize localized overheating.
4.5.1. Automatic Pipette—Eppendorf or equivalent of adequate capacity to obtain a 1 .0-rnL sample.
4.5.2. Filter Funnel—-Buchner or equivalent and filter paper, filter flask, and a vacuum source.
4.5.3. Glassware—l00- and 250-mL flasks.
5. TEST SPEMENS
5.1. Test specimens may be either laboratory-mixed HMA or sampled from HMA pavements.
5.2. Pavement specimens shall be taken from pavements with a core drill, diamond or carborundum saw, or by other suitable means. Specimens will be further prepared as noted in Section 6.1.
5.3. Specimens shall be free from foreign materials such as foundation material, soil, paper, foil. etc.
5.4. If the core contains more than one pavement layer, it is recommended that the layers be separated by sawing or other suitable means.
6.1. Preparation of Specimen:
6.1.1. A specimen is obtained from the drilling dust of a pavement core or laboratory-mixed IIMA sample. Stand the core on a thick piece of wood and use a heavy-duty rotary hammer with a carbide bit to drill into the sample.
Note 1—A rotary hammer that utilizes SDS, SDS Max, or spline shank bits is recommended. Devices utilizing straight shank bits have been found to be insufficient. Depending upon the number of samples, it may be worthwhile to make a frame to hold the core.
Note 2—It is recommended to wear safety glasses and protective gloves.
6.1.2. Drill to the depth of the drill flutes. This depth will yield about 15 g of dust. Discard any lumps of the core that may break off.AASHTO TP 72 pdf download.