Density / Relative Compaction.
Calculated.
The Caltrans in-place HMA density workbook, with every formula wired. Random stations, core correlation, gauge averages, relative density — done the moment you type the readings.
Every line
calculated.
The workbook follows Caltrans TL-3112 (REV 08/2026) line for line and works the calculations the form calls for. You type the readings and project data. The sheet does the arithmetic and flags what to check.
Random locations, per spec
Picks the CT 375 table and block, sorts the pairs by station, and lays out up to ten test sites. No hand-rolling, no napkin math.
Station & offset math
Longitudinal I = D × G, station I + B, transverse E × H, rounded up the way CT 375 wants them, with edge sites moved to 1 ft.
Gauge density, a and b
Both readings at every site, averaged to 0.01 g/cc, with RETEST when they differ by more than 0.05 g/cc (CT 375, 4B.9).
Core correlation
The worksheet turns core-minus-gauge differences into the correlation factor and applies it: O = M + N.
Relative density
Computes S = O / Gmm to the nearest 0.1 % and checks it against the 91.0–97.0 % spec range (Type A HMA).
Current form, and the 2004 one
TL-3112 (REV 08/2026) line for line, and the 2004 form for contracts that still call for it. Each prints to one Letter page as a PDF.
A 0.4% math error
is a rejected lot.
Type A HMA cores have to land between 91.0 and 97.0 % of maximum theoretical density. Outside that, the engineer deducts pay or rejects the lot. One transposed reading, one bad average, and a sublot that passed in the field fails on paper.
Caltrans Section 39 calls for gauge density tests at 3 per 250 tons (or 3 per paving day), with the gauge correlated to cores on day one under CT 375. Every test runs through TL-3112. Every result is argued over when it's close to the limits.
This workbook does the arithmetic and shows its work: every formula is in the open for QC or the RE to check. You spend your time where judgment actually matters: the gauge seat, the lift thickness, the cold joint.
- 01Core density, Type A HMA (% of Gmm)91.0–97.0
- 02Gauge density tests, minimum3 / 250 t
- 03Relative density reported to nearest0.1 %
- 04Density rounded to nearest0.01 g/cc
- 05Gauge-to-core correlationDay 1
- 06Test sites per test area (CT 375)5–10