US SPEC MP Grout must pass the requirements laid forth in ASTM C1107 Standard Specification for Packaged Dry, Hydraulic-Cement Grout (Nonshrink). One of those requirements is passing the height change values defined within C1107. This testing is performed by using ASTM C1090 Standard Test Method for Measuring Changes in Height of Cylindrical Specimens of Hydraulic-Cement Grout. The pictures are of the apparatus used for this testing. The cylinder is filled to the rim, then a glass plate is placed on top of the cylinder. The center piece at the top is lowered to hold the glass in place while the grout sets. After 24 hours the glass plate is removed and the grout allowed to freely expand/shrink during the 28 day curing period. The caliper is used to take readings at initial, 1 day, 3 day, 14 day and 28 day intervals. This will then give you the measurements to determine if the grout falls within the standard specification.