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| Step 1 - Determine Operating Pressure |
| Place shims around the open end of the cyclinder to provide an opening for water to enter during the test. |
| Invert the cylinder in bowl, set the spring on the top of the cylinder and clamp the conical cover to the flamge of the bowl. |
| Remove the top cap, insert the spray tube and funnel and fill with water. |
| Remove the spray tube and funnel and add water to fill indicator |
| Replace top cap and pump until water level is half way down on gage |
| Tilt the assembly and rotate bowl three or four times using the edge of the bowl as a piviot, tapping the cover to remove air bubbles. |
| Return to vertical position, remove cap, and add water to exactly zero on the indicator |
| Replace cap and pressurize until water is lowered to .98R units (R is the ratio of the volume of the cylinder to the volume of the measuring bowl). The reading on the gage is the pressure to be used to determine an expansion factor in step 2 |
| Step 2 - Determine Expansion Factor for Indicator |
| If the indicator is made of steel this stem can be neglected |
| Fill the assembled indicator with water |
| Apply the pressure developed from Step 1 |
| The amount that the water column lowers is the expansion factor |
| Step 3 - Determine Exact Operating Pressure |
| If the indicator is constructed of steel the pressure determined in Step 1 is the Exact Operating Pressure to be used. |
| With the expansion factor determined, repeat the procedure outlined in Step 1, excluding the last item. |
| Replace the cap, apply pressure until the water has been lowered to .98R + expansion factor units on the glass gage. |
| Tap lightly and read pressure gage. |
| To check release pressure and apply air until pressure read above is achieved. If water column is .98R + expansion factor, use this pressure as operating pressure. If not repeat test until good readings are achieved. |
| The exact operating pressure to be used is the pressure found above minus .1 psi. The .1 psi is a correction factor due to the difference between the distribution of air in the sample and in the calibration cylinder. |
| Step 4 - Determine Aggregrate Correction Factor |
| This test may be performed once for a defined aggregate type but is recommended to be checked occasionally. |
| Fill the bowl 1/3 full of water and one part of sand to two parts of coarse aggregate. Bowl should be full and sides should be tapped to remove entrapped air |
| Strike off free foam from top, clean flanges and install the conical cover. |
| Remove the top cap, insert the spray tube and funneland add water to half way mark on glass tube. |
| Remove spray tube and funnel and place the palm of hand over the top, incline from vertical and move the assembly in several circles, using the bowl as a piviot to remove entrapped air. |
| Return to vertical and fill column to the zero mark. |
| Replace cap and apply .2 psi more than the operating pressure. |
| Tap bowl and when air gage reads operating pressure read and record water level. |
| Release pressure slowly to about 1 psi by looosening cap. Remove cap and tap bowl for about one minute then read and record water level. |
| The aggregate correction factor will be h1 - h2 |
| Repeat this procedure until two concurrent tests show a correction factor within 0.2 percentage points. |
| Step 4 - Determine Entrained Air Content |
| Fill bowl in three equal layers, rodding each layer about 25 strokes. After rodding each layer tap sides with soft hammer 10 to 15 times. |
| The bowl should be slightly overfilled then struck off flush with a strike off bar |
| Clean flanges and install the conical cover. |
| Remove the top cap, insert the spray tube and funnel and add water to half way mark on glass tube. |
| Remove spray tube and funnel and place the palm of hand over the top, incline from vertical and move the assembly in several circles, using the bowl as a piviot to remove entrapped air. |
| Return to vertical and fill column to the zero mark. |
| Replace cap and apply .2 psi more than the operating pressure. |
| Tap bowl and when air gage reads operating pressure read and record water level. |
| Release pressure slowly to about 1 psi by looosening cap. Remove cap and tap bowl for about one minute then read and record water level. |
| The entrained air content is equal to ther reading minus the aggregate correction factor. |
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