AASHTO M 307:13(2017) Standard Specification for Silica Fume Used in Cementitious Mixtures.
7.3.2. MI samples, whether grab or composite, shall have a mass of at least 1 kg (2 Ib).
7.3.3. When compliance verification tests of silica fume are required to be made at a laboratory other than that of the silica fume manufacturer or marketer, coordinate the silica fume sampling schedule, sample transportation time, and sample testing schedule among the purchaser, manufacturer, and testing laboratory so the test results will be available when the decision to accept or reject the silica fume must be made.
7.3.4. The section entitled 6Sampling is modified as follows:
184.108.40.206. Take two grab samples or two composite samples for the first 100 Mg (110 tons) of silica fume. Take a grab sample or a composite sample for each subsequent 100 Mg (110 tons) of silica fume. but not less than two samples shall be taken in any sampling program.
220.127.116.11. Fl-oil? Bulk Storage at Points of Discharge—Withd raw silica fume from the discharge openings in a steady stream until sampling is completed. In sampling bulk storage at points of discharge, while the silica fume is flowing through the openings, take samples at such intervals so that, at a minimum, the sampling requirements of Section 18.104.22.168 are met.
7.3.5. The section entitled bAmount of Testing” is modified by deleting the first paragraph, “General.”
8. FREQUENCY OF TESTS
8.1. Except for the tests listed in Section 8.2, make all chemical determinations and physical tests on composite samples representing no more than 400 Mg (440 tons) each. Prepare each composite sample by combining portions from the samples representing each 100 Mg (110 tons) so that each 100 Mg (110 tons) is represented equally.
8.2. Test for specific surface, density, and accelerated pozzolanic strength activity index using composite samples that represent 3200 Mg (3520 tons) or 3 mos of production, whichever gives the highest frequency. Prepare each composite sample by combining portions from the samples representing each 400 Mg (440 tons) or I mo, whichever gives the highest frequency, so that each sample is represented equally.
9. PREPARATION OF SAMPLE
9.1. Prepare composite samples for tests, as required in Section 8, by arranging all test samples in groups, with each group representing the number of megagrams required by the test or tests for which the composite sample is intended. From each of the samples in a group. take equal portions, sufficient in amount to form a composite sample large enough to permit making the required physical or chemical determinations.
9.2. Prior to testing, mix grab samples and composite samples thoroughly. A clean and dry laboratory concrete drum mixer provides adequate mixing for this purpose. Take care to limit the volume of silica fume in the drum mixer to the range of 10 to 50 percent of the drum’s total capacity. If necessary, secure a sheet of polyethylene film on the drum with an elastic tiedown to keep the material in the drum. Limit the mixing action to 5 ± 1 min.
9.2.1. When a small sample size precludes the use of a concrete mixer, use a heavy plastic bag, of a capacity at least five times larger than the sample volume, to mix the sample thoroughly. After placing the sample in the bag, close the bag by tying the bag opening tightly, and mix the material by rolling the bag around for 5 ± 1 min.AASHTO M 307 pdf download.