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Figure 8-2. Guidelines for reconciling the VMA difference between the laboratory designed and plant produced HMA mixes.
Check VMA - if meet JMF - ok. If does not meet JMF - Check mix composition: asphalt content and gradation (including P200). If does not meet JMF - Make necessary adjustment to HMA production to meet JMF composition then back to check mix composition...
Meet JMF has two options the first is VMA has major deviation from JMF (> 0.3%). The second is VMA has minor deviation from JMF (<0.3%). For VMA has major deviation from JMF (> 0.3%) - Does the mix have natural sand. If yes adjust the amount of natural sand. Decrease the amount to increase VMA - Produce HMA and recheck VMA. - OK stop. If not OK adjust the percent passing No. 8 (fine/coarse aggregate proportion). Deviated from the MDL or use data from extend mix design. OK stop, Not OK - redesign. If does mix have natural sand go to 'Adjust the percent passing No. 8...' above.
If Meet JMF is VMA has minor deviation form JMF (<0.3 %) - Adjust P200; Decrease P200 by 1% to increase VMA by 0.3% or use extended mix design curve. If OK stop. If not OK go to does mix have natural sand above.
Figure 8-3. Guidelines for reconciling the VTM difference between the laboratory designed and plant produced HMA mixes.
Check VMT - If meet JMF - OK. If Does not meet JMF - Check mix composition: Asphalt content and gradation (including P200). If Does not meet JMF - Make necessary adjustment to HMA to production to meet JMF composition. Return to check mix composition. If Meet JMF - If VTM has major deviation from JMF (>0.5%) - Adjust asphalt content; decrease asphalt content to increase VTM. Use Table A or extend mix design. - Produce HMA mix and recheck. If ok stop. If not ok, redesign.
If Meet JMF is VTM has minor deviation form JMF (<0.5%) - Adjust P200: Decrease P200 to increase VTM. Use Table A or extended mix design - Produce HMA mix and recheck VTM. If ok stop. If not ok, got to Adjust asphalt content; decrease asphalt content to increase VTM. Use Table A or extend mix design from above.
VMA (Percent) | Change in VTM for every percent change in | |
---|---|---|
P200 | AC | |
12 | - | -1.35 |
13 | -0.02 | -1.21 |
14 | -0.10 | -1.07 |
15 | -0.17 | -0.93 |
16 | -0.25 | -0.78 |
17 | -0.33 | -0.64 |
18 | -0.40 | -0.50 |
Figure 12-1. Different steps in cold mix recycling.
Prepare Construction Area - If Pulverize pavement and base material - go to Add and mix new aggregate and/or stabilizing agent. If Rip and Break up pavement and base materials - if pulverize on-grade - haul to central plant - go to Add and mix new aggregate and/or stabilizing agent. If Haul to central plant - crush at plant - go to Add and mix new aggregate and/or stabilizing agent.
Add and mix new aggregate and/or stabilizing agent - haul to grade - fine grade or place with a conventional paver and compact - tack and place surface course as required.
Figure 16-1. Flow chart for full depth reclamation.(4)
Step 1 Prepare construction area.
Step 2a - Pulverize, add and mix stabilizing agent, place on grade with single machine. Compact. Tack and place surface course as required.
Step 2b - Pulverize, add and mix stabilizing agent, place on grade with equipment train. Compact. Tack and place surface course as required.
Step 2c - Rip and break up asphalt concrete surfaces. Windrow material. Pulverize pavement and base material. Then either add and mix stabilizing agents. Fine grad and compact. Tack and place surface course as required. Or fine grad and compact. Prime and place surface course as required.
Step 2d - Pulverize pavement and bas material with multiple and two-step sequences. Then either add and mix stabilizing agent. Fine grad and compact. Tack and place surface course as required. Or fine grade and compact. Prime and place surface course as required.
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