Grout Pumping and Injection Operations TR 003 The need for QA testing is already explained in the introduction but to recap, it is important to ensure that the grout we are injecting is tested, recorded & compared to the specifications on mix charts. Knowing that the grout injected was as per specifications allows us to analyse the results of the grouting works carried out with some degree of confidence. The typical QA tests conducted on the mixed grout, at the mixing site, are as follows; ▪ Mud Balance (density) ▪ Marsh Flow (viscosity) ▪ Bleed (stability) ▪ Cast cubes for compressive strength (only if required) 2.4. Mud Balance – or Density Test. This is a very quick and effective test to verify that the materials have been batched in the correct proportions and that the grout is properly mixed. Each grout mix has a theoretical density figure on the batch card and we can make a direct comparison of the actual test figure against the theoretical figure. In the example, the theoretical density is given as 1643kg/m3 ± 2% or say ± 30kg/m3. So if the Mud balance density comes out as 1610 – 1670 kg/m3, then this is within specification. If not, then a mistake has been made with batching. After taking a sample of fresh grout, the test is performed as follows;
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