Sampling and Testing

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Samples of the slurry shall be taken from near-bottom of the excavation (about 90% of depth), from the upper portion of the excavation, and from the slurry supply tanks (if applicable) at regular intervals during the excavating process, in order to facilitate control of slurry properties.

During the excavation of each discrete element such as a borehole or a wall panel, slurry samples shall be taken from near-bottom and upper portion at least once during the excavation of each element, and not less than once every four hours, except for overnight shutdowns. When operating conditions make it prudent to sample and test more frequently, sampling and testing shall be done in accordance with a schedule recommended by the Manufacturer or the contractor and approved by the Engineer.

Samples shall be collected with a suitable device (double ball bailer) that captures representative samples of sufficient volume (≥ 1.8 liters or 2 quarts) to perform required testing of the slurry. Samples collected as described above shall be tested for Marsh Funnel Viscosity, pH and specific weight. A written record shall be maintained, showing viscosities, pH values, specific weights, dates, times, excavation identifiers, depths or locations from which samples were taken (excavation, supply tank, mix tank) and other pertinent information as and if specified by the Engineer. Testing of specific weight and sand content may be required by the Engineer before placement of reinforcing steel and concrete, if specifications for these parameters are in force for the project.