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 cell
audited.
The workbook mirrors Caltrans TL-3112 (REV 08/2026) line for line and runs every calculation the form requires. You type the readings and project data. The sheet does the arithmetic — and the policing.
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, plus the 2004 form for contracts that still use TMD. Each with a worked example; one Letter page to 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 removes the arithmetic from the argument. Hand it to a contractor's QC, hand it to the RE — the formulas are the formulas. 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
- 06Typical time saved per sublot~20 min
Send me the workbook.
Drop your email. The file lands in your inbox and the download starts immediately. You'll get the occasional update when we ship a new CT tool — nothing else.
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Terms
The workbook is free to use and is provided as is. It follows California Test 375 (February 2012) and Form TL-3112 (REV 08/2026), but you are responsible for checking its results against the current test method and your contract's specifications before relying on them. Bunker Inspections is not affiliated with Caltrans.