"Hot Mix Asphalt Tonnage and the Spread-Rate Check" is lesson 1 of 6 in the Earthwork and Paving (C-12) Learning Hub. It opens with "HMA Is Bought and Paid for by the Ton" and works through 6 short steps, then a worked example you can check yourself against.
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Steps in this lesson
HMA Is Bought and Paid for by the Ton
Know the Unit Weight - and Label Your Assumption
The Tonnage Formula
The Spread-Rate Check: Pounds per Linear Foot
Act on the Difference While the Mat Is Hot
Thickness and Density Limits the Spec Prints
The worked example in the course applies this lesson to a realistic job in 7 steps, from "Convert thickness to feet" through "Cost of the error".
What you'll be able to do
Explain the main idea of "Hot Mix Asphalt Tonnage and the Spread-Rate Check" in plain language you can use on the exam.
Apply this step with confidence: "The Tonnage Formula".
Apply this step with confidence: "The Spread-Rate Check: Pounds per Linear Foot".
Apply this step with confidence: "Act on the Difference While the Mat Is Hot".
Apply this step with confidence: "Thickness and Density Limits the Spec Prints".
Test yourself on the worked example and the quick-check quiz inside the classroom.
The diagram for this lesson, exactly as it appears in the Learning Hub.
The first steps of this lesson
Step 1: HMA Is Bought and Paid for by the Ton
The plans give you an area and a thickness, but the asphalt plant sells by the ton and the owner pays by the ton. On Caltrans work the payment quantity for hot mix asphalt (HMA) is measured on the combined mixture weight (2025 Caltrans Standard Specifications section 39-2.01D), the contractor submits a public weighmaster certificate for HMA (section 9-1.07A), and every scale must be run by a licensed weighmaster (section 9-1.02B). The weighed tickets, not the plan area, decide the tons. That means a mat that is a little too thick is not just a quality quirk - every extra tenth of an inch is more tons placed.
Step 2: Know the Unit Weight - and Label Your Assumption
To turn a volume into weight you need the in-place weight of the compacted mix per cubic foot. The Standard Specifications do not hand you that figure; it comes from the mix design and the plant tickets for the job. This lesson uses 150 pounds per cubic foot as a labeled example value only. A shortcut falls out of the same number: one square yard, one inch thick is 9 sq ft x (1/12) ft = 0.75 cu ft, and 0.75 x 150 = 112.5 lb. Change the unit weight and the shortcut changes with it, so never carry a remembered shortcut from one mix to another.
The remaining 4 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.
Independent exam preparation. Contractors Classroom is not affiliated with the Contractors State License Board, and no course can guarantee a passing result.
