The thermometer is placed to provide at least 3 inches of concrete around the Here, the temperature is being taken after concrete placement, but ideally it should be taken prior to placement to respond to temperatures outside of a specified range. They are then covered to protect against rapid evaporation and to avoid contamination. These samples must be taken no more than 15 minutes apart and remixed to yield a composite sample. The guidelines are to take composite samples of sufficient total volume (1 ft 3 minimum) from the ready-mix truck after 10% and before 90% of the load has been discharged. Sampling (per ASTM C 172) is the first step in determining if the concrete placed complies with specifications. Although sampling and making and curing test specimens are not test methods per se, they are important practices because subsequent tests depend on the manner in which the concrete was sampled and the manner in which the test samples were made.įor more detailed information on these and other test procedures, visit Another good resource is ACI 214, Recommended Practice for Evaluation of Strength Tests Results of Concrete, available from the American Concrete Institute. Data from these tests is helpful in assessing mix production and consistency in performance.
Fresh concrete tests run along with a set of compressive strength cylinders are: slump, air content, unit weight and temperature. Each procedure or test method must be conducted properly and within the required time frame to be comparable. If you work in the concrete industry, your work or your materials are likely to be affected by these test results. Making and Curing Concrete Test Specimens in the Field So what tests are typically run (or would be beneficial to conduct) on a smaller-size construction project? Here's a basic checklist: ASTM C 172Īir Content of Fresh Concrete by the Pressure MethodĪir Content of Fresh Concrete by the Volumetric Method (Roll-o-meter)ĭensity (Unit Weight), Yield and Air Content of Concrete This will give you the greatest assurance that proper sampling and proper field and laboratory tests are conducted. You should take concrete testing seriously and start off on the right foot by securing the services of a certified testing laboratory (see ASTM C 1077) employing field and lab technicians that are ACI-certified. Need your concrete tested? Find concrete contractors near me. Was excess water added? Was the air content too high or too low? Fresh concrete test data such as slump and air content can help indicate possible causes and guide the troubleshooting investigation. Assessing the properties of fresh concrete during placement leaves a contractor in a better position to respond to any problems that ensue, such as low strength or cracking.
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