CCRL Proficiency Sample Programs support accreditation programs conducted by others. Participation in proficiency sample programs also permit laboratories to check consistency of their testing. Results from such programs can be used to evaluate quality of testing between laboratories, and to help identify problems with equipment or procedures. Laboratories are required by ASTM C1093, C1077, and C1222 to participate in a proficiency sample program.
The Proficiency Sample Programs were developed as a means for a laboratory to monitor the quality of its testing between CCRL on-site assessments. The programs are overseen by ASTM Committees C-1 on Cement and C-9 on Concrete and Concrete Aggregates, and payment is made to ASTM. The Proficiency Sample Programs are based on the two-sample system described in papers by Youden [1], and by Crandall and Blaine [2] in the 1959 Proceedings of the American Society for Testing and Materials.
All programs are conducted in a similar manner. At intervals of 12 months, quantities of two slightly different lots of a material (cements, pozzolans, concrete aggregates, masonry sand, masonry units, and reinforcing bars) are procured from commercial sources. This material is then homogenized using well defined procedures and divided into individual test samples at the CCRL facility. Special instructions, and all necessary reporting forms, are made available on our website, for each set of samples. The test procedures to be performed are taken from current ASTM specifications. The specified tests included in each program are made available to perform. It is the responsibility of the participant to determine which tests they wish to perform. The results are then reported to the CCRL for review and evaluation. Test results reported by an individual laboratory are treated confidentially as to source. Approximately nine weeks after the samples are distributed, when the program closes, a preliminary report is made available for participants to review on the website, showing tentative average values and standard deviations for each determination, based on a limited number of returned results.
Within three weeks, the final results are made available on our website for review. These results contains average values, standard deviations based on all applicable data, and scatter diagrams. In addition, precision values and other statistical information are produced for use by ASTM committees and other interested organizations. Scatter diagrams are generated on our website for each test performed by the laboratories. For each pair of samples, the test results of the odd-numbered sample are plotted on the X (horizontal) axis, and the results of the even-numbered sample are plotted on the Y (vertical) axis. A substantial variation of its test values from the center of the diagram is generally of concern to a laboratory. A continuing trend of large variations indicates a need for some corrective action, either in apparatus or technique. To focus attention on significant deviations from the average, each laboratory is given a rating on each determination using a rating scale based on the standard deviation. The ratings have no significance beyond indicating the difference between the individual laboratory result and the average for a particular test. To help give meaning to the ratings obtained by an individual laboratory over a given period of time, performance charts are generated on our website. These charts visually show a participant's deviation from the average value on the ten most recent sample pairs, thereby providing a means of monitoring the general tendencies and bias of a laboratory's test results. This information gives some indication of a laboratory's overall proficiency for given tests.
The Portland Cement Proficiency Sample Program provides for the distribution of a pair of chemical and physical test samples of Portland Cement once per year, with shipping occurring in January. Samples for the physical tests weigh approximately 9 kg each, and are packaged in plastic bags. Samples for the chemical analyses weigh approximately 20 grams each, and are packed in glass vials. The deadline to enroll for January is November 1st. The physical determinations to be made on each sample cover the tests for portland cement to which reference is made in the current edition of ASTM Standard Specification for Portland Cement (C150), and include the following:
The same cement is used for both chemical and physical tests. Normally, one vial is furnished with each chemical sample. Additional vials for use in instrumental determinations may be obtained, if requested in advance of the indicated distribution dates. The chemical tests (ASTM C114) to be performed include the following:
Unless otherwise specified, the procedure to be used in making these tests is the one customarily followed by the laboratory.
The Blended Cement Proficiency Sample Program provides for the distribution of one pair of chemical and physical test samples per year. Samples for the physical tests weigh approximately 8 kg each, and are packaged in plastic bags. Samples for the chemical analyses weigh approximately 20 grams each, and are packed in glass vials. Samples are shipped to participants in February. The deadline to enroll is November 1st. Physical and chemical determinations on each sample are to be made in accordance with the current edition of the ASTM Specification for Blended Hydraulic Cements (C595) and the various standards and specifications to which it refers.
The physical tests to be performed include the following:
The cement used for the chemical tests is the same as that used for the physical tests. The chemical tests (ASTM C114) to be performed are as follows:
Unless otherwise specified, the procedure to be used in making these tests is the one customarily followed by the laboratory.
The Portland-Limestone Cement (hereafter referred to as PLC) Proficiency Sample Program provides for the distribution of a pair of chemical and physical test samples of PLC once per year. Samples for the physical tests weigh approximately 9 kg each, and are packaged in plastic bags. Samples for the chemical analyses weigh approximately 20 grams each, and are packed in glass vials. Samples are shipped to participants in June. The deadline to enroll is March 1st. Physical and chemical determinations on each sample are to be made in accordance with the current edition of the ASTM Specification for Blended Hydraulic Cements (C595) and the various standards and specifications to which it refers. For those tests not required in ASTM C595, reference should be made to the current edition of ASTM Standard Specification for Portland Cement (C150).
The physical tests to be performed include the following:
The same cement is used for both chemical tests and physical tests. Normally, one vial is furnished with each chemical sample. The chemical tests (ASTM C114) available to be performed are as follows:
Unless otherwise specified, the procedure to be used in making these tests is the one customarily followed by the laboratory.
Unless otherwise specified, the procedure to be used in making these tests is the one customarily followed by the laboratory.
The Pozzolan Proficiency Sample Program provides for the distribution of a pair of chemical and physical test samples. Both pozzolans used for the chemical sample pair are either ASTM Class C or Class F fly ashes. Samples for the chemical analysis weigh approximately 30 grams each, and are packaged in glass vials. Samples for physical testing include approximately 2.3 kg each of pozzolan,and approximately 18 kg of a companion portland cement. Samples are shipped to participants in March. The deadline to enroll is November 1st. Physical and chemical determinations on each sample are to be made in accordance with the current edition of the ASTM Standard Test Method for Sampling and Testing Fly Ash or Natural Pozzolans for Use as a Mineral Admixture in Portland-Cement Concrete (C311) and the various methods to which it refers. The tests to be performed are taken from current ASTM Specification C311 and include the following test methods as modified by C311:
The chemical tests (ASTM C114) to be performed include the following:
Unless otherwise specified, the procedure to be used in making these tests is the one customarily followed by the laboratory.
The Concrete Proficiency Sample Program provides for the distribution of a pair of samples once per year (in the fall). For each individual sample portland cement, coarse aggregate, and fine aggregate are packaged separately. The quantity of material needed for this sample makes it necessary to send the sample pair in six boxes, each weighing between 23 and 73 pounds (10.5 to 33 kilograms). The material furnished in each sample is sufficient to perform tests for slump, air content, unit weight, and to make two 6 by 12 inch (150 by 300 mm), or three 4 by 8 inch (100 by 200 mm) test cylinders. Samples are shipped to participants between August and November. The deadline to enroll for August is May 1st. There is an option to include ASTM 78, Standard Test Method for Flexural Strength of Concrete (using Simple Beam with Third-Point Loading), as an additional test, for an additional fee. If participating in this test (C78), the quantity of material needed for each sample will double, with participants receiving two boxes of cement, two boxes of fine aggregate, and two boxes of coarse aggregate for each sample pair. Therefore, a participant in the concrete proficiency sample with the the C78 option will receive twelve boxes. The additional material, mixed at the same time as the rest of the sample, is used to make two 6 by 6 inch (150 by 150 mm) concrete beams. Unless participating in the optional C78 test, a concrete mixer with a one cubic foot batch capacity is required to mix each concrete sample. If participating in the optional C78 test, a concrete mixer with a two cubic foot batch capacity will be necessary. The ASTM standards on which prescribed tests are based are as follows:
The Masonry Mortar program provides for the distribution of one pair of test samples per year. The cement portion of each sample weighs approximately 7 kg and is packaged in plastic bags. The masonry sand portion, used for both samples, is packaged in one container of 15kg. The materials for the sample are purchased from commercial sources, homogenized and packaged, and then shipped to the participants. Samples are shipped to participants in July. The deadline to enroll is March 1st. The tests to be performed are taken from current ASTM Specification C270 and include the following test methods as modified by C270:
The Concrete Masonry Unit program provides for the distribution of one pair of test samples per year. Each sample consists of six 4x8x8 inch units for a total of twelve units. The units are procured with the help of the National Concrete Masonry Association (NCMA). Each unit is weighed and categorized, and then packaged. The units are packaged in specially designed corrugated boxes to prevent damage, and mailed to participants. Samples are shipped to participants in May. The deadline to enroll is January 1st. The tests to be performed are taken from current ASTM Specification C140 and include the following:
The Steel Reinforcing Bar program provide for the distribution of one pair of test samples per year. Each sample consists of three bars approximately 28 inches in length usually conforming to A615 orA706. The specimens are cut, randomize, and packaged by CCRL. Samples are shipped to participants in April. The deadline to enroll is January 1st. Tests to be performed the following:
The ASR program distributes one pair of test samples per year in June. The deadline to enroll is March 1st. Two fine aggregates, each weighing around 4000g, are included. One package of portland cement weighing around 2500 g is supplied for use with both fine aggregates.
The fine aggregates are ASTM C33 fine aggregates and the portland cement is an ASTM C150 cement conforming to the ASTM C151 expansion limits listed in ASTM C1260. These materials are purchased from commercial sources, homogenized and packaged for uniformity and then distributed to participating laboratories.
The test results reported by participating laboratories are found in the current ASTM Test Method C1260 Potential Alkali Reactivity of Aggregates (Mortar-Bar Method) and include:
Laboratory ratings will be assigned for the 14 & 28 day readings.
A laboratory wishing to join any of the programs may do so by sending a request form along with a check made out to ASTM for the full amount of the sample. The appropriate request form with program fee can be obtained by contacting CCRL at ccrl@astm.org or 240-436-4800. On receipt of the request form and payment, the laboratory is added to the list of participants, sent a letter of confirmation, and given an individualized laboratory identification number. Requests received less than 60 days prior to the sample distribution cannot be ensured enrollment in the current sample.