<p>Reference(s):</p> <p>ASTM D4380 (2012)</p> <p>Farnsworth et al. (2010)</p> <p>PTI Committee DC35 (2014)</p> <p>&nbsp;</p> <p><strong>Method Summary</strong></p> <p>The mud balance test is a method to find the specific gravity of a slurry. Grout in its fluid state behaves as a slurry and this test method can be used to find the specific gravity of the grout mixture. For neat grout, which contains only water and cement, the relationship between specific gravity, water-cement ratio, and compressive strength is well defined. A mud balance consists of a cup attached to a sliding weight. The cup with a known volume is filled with grout. The sliding counterweight is adjusted until equilibrium is achieved and the balance is calibrated to measure the density directly. The density of grout is converted to specific gravity then converted to projected compressive strength.</p> <p><strong>Accuracy and Precision</strong></p> <p>The test method has been proven to be accurate and precise with neat grout mixes.</p> <p><strong>Adequacy of Coverage</strong></p> <p>One mud balance test should be conducted for each batch of grout to be used on a project.</p> <p><strong>Implementation Requirements</strong></p> <p>The testing method requires a mud balance, which is a mechanical balance consisting of a graduated beam and a mud cup balanced over an intermediate knife-edge point. Weights are used in conjunction with the balance set up to find the mass of the mud present.</p> <p><strong>General Comments</strong></p> <p>This is a very advantageous compressive strength testing method because it is non-destructive and the results are found immediately after mixing.</p>