Position: This page describes the weighing method for hydrated lime and asphalt weighing and mixing.
1. SCOPE
This method applies to the verification of hydrated lime weighing systems for hot-mix asphalt.
2. SIGNIFICANCE AND USE
The purpose of this procedure is to check the lime rate to ensure that the lime rate meets SCDOT specifications to prevent asphalt mixtures from stripping.
3. APPARATUS
Four 50-pound test weights that are certified once a year by an authorized public official or scale servicer. Documentation of weight certifications shall be maintained in the field laboratory.
4. PROCEDURE
4.1. With the weigh pod empty, record the scale weighing indicator reading on SCDOT Form 400.14.
4.2. Apply all four test weights and record the scale indicator reading. The display reading on the scale indicator is to be within ±20 pounds of the actual weight when the four 50-pound weights (200 pounds) are attached to the empty weigh pod.
4.3. The weigh pod is to be loaded approximately half full with hydrated lime with four 50-pound weights attached. Record the scale indicator reading on Form 400.14 for verification.
4.4. Remove the four 50-pound weights one at a time and record the scale indicator reading on Laboratory Form 979. The scale indicator reading in the control room shall reflect the weight changes to within ±5 pounds of the actual weight on the weigh pod.
5. CALCULATIONS
When performing the procedures in Section 4, the scale weight is subtracted from the actual calculated weight and its absolute value is compared to the allowable tolerance.
6. REPORT
The actual weight difference shall be within the allowable tolerance of ±5 pounds for each 50-pound test weight removed. All data must be reported on SCDOT Form 400.05 – Daily Report of Asphalt Plant Inspection and calculations recorded on SCDOT Form 400.14 – Verification of Hydrated Lime Weighing Systems with weighing controllers for Hot Mix Asphalt.
SCDOT Designation: SC-T-78 (9/08)
