Rice testing determines the maximum specific gravity of bituminous paving mixtures. Vacuum pycnometers work with vibrating tables and de-airing agitators to keep sample materials loose for more reliable test results. Â The vacuum saturation canister conditions specimens before testing. It has an acrylic lid with ports for a vacuum pump and manometer. Two stage vacuum pumps operate for distillation, filtration, and degassing. Also available: indicating dessicant that start blue and changes to pink upon absorption of moisture. Â The color change is pronounce and clearly visible. Making the drierite valuable in knowing with certainty that dryness is being maintained and to signal when drying agent should be replaced.