Paving and concrete terms, explained plainly

A

Aggregate base: A layer of compacted crushed stone between the subgrade and an asphalt or concrete surface that spreads the load, drains water and keeps the pavement up.
Air entrainment: Adding an admixture to concrete that creates billions of tiny air bubbles, which give freezing water room to expand so the slab doesn't scale or crack.
Asphalt overlay: A new lift of hot mix paved on top of existing asphalt without removing it, raising the grade by the lift thickness, which is often 1.5 to 2 inches on a lot.
Asphalt tonnage: The weight of hot mix a job needs, in short tons of 2,000 lb: area in square feet times depth in inches, divided by 12, times unit weight, divided by 2,000.
Asphalt yield: The tons of hot mix a job actually used, from the plant tickets, divided by the tons the estimate figured from area, depth and unit weight. Over 1 is heavy.

Broom finish: A texture made by dragging a broom across fresh concrete after floating, leaving fine ridges that give sidewalks, driveways and ramps traction when wet.

Change order: A written change to a job's work, price or schedule, signed by the customer before the changed work starts. On paving jobs, soft base is the usual reason.
Compaction factor: The ratio of a material's loose volume as it's spread to its volume after compaction, used to set the screed and to order enough stone to reach grade.
Concrete curing: Keeping new concrete moist and at a workable temperature for its first days so the cement keeps hydrating and the slab reaches the strength it was designed for.
Concrete psi: A concrete mix's specified compressive strength in pounds per square inch at 28 days, confirmed by breaking cylinders cast from the load, like 4,000 psi.
Concrete slump: How far fresh concrete sags when a 12-inch cone of it is lifted away, in inches. It measures how wet and workable the mix is, not how strong it will be.
Control joint: A groove tooled or sawn into a concrete slab to make a weak line, so when the concrete shrinks and cracks, it cracks there. Also called a contraction joint.
Crack sealing: Cleaning cracks in asphalt and sealing them with hot-applied rubberized sealant to keep water out of the base, priced by the foot and done before sealcoat.

Job closeout: The office work that finishes a job after the crew leaves: final invoice checked against the signed proposal and change orders, retainage requested, subs paid.
Job number: A job's short number, such as J-0142, given when a request becomes a job, so dispatch, the crew and the office can all say which job they mean on the phone.
Job team: The four roles every job has, the salesperson, project manager, superintendent and foreman, one person in each, so the right person hears the right news.

Lift thickness: The compacted depth of one layer of hot mix placed in a single pass of the paver, stated in inches and used with the area and unit weight to figure tons.
Line striping: Painting parking stalls, arrows, accessible stall symbols, fire lanes and curb markings on pavement, done last on a lot and priced by the stall and the piece.

Mill and fill: Removing a set depth of old asphalt with a milling machine and paving a new lift back in its place at the same finished grade. Also called mill and overlay.
Mobilization: The cost of moving crews, equipment and material to a job and setting up to start, carried as a proposal line and charged again if the crew has to come back.

Photo pair: A before photo and an after photo of the same spot on a job, shown side by side with a short caption, the quickest proof of what the crew did.
Progress billing: Invoicing a customer at set intervals during a job for the work done so far, against a schedule of values and less retainage, instead of once at the end.
Proposal: The document a customer gets from a contractor to read and sign: the priced work, grouped by trade, with the total and how long the price holds.
Punch list: A list of items still to fix or finish once the main work on a job is done, walked with the customer and closed item by item before final payment is released.

Request: Work that's come in but hasn't been taken on yet: a phone call, a website form or a GC's plan set, until it's converted to a job or declined.
Retainage: A percentage of each progress payment that an owner or general contractor holds back until the project is complete and accepted, as security that you'll finish.

Schedule of values: A breakdown of the contract price into lines with dollar values, agreed before work starts, used to bill each month for the percent of each line complete.
Scope of work: The written description of what a contractor will do on a job: quantities, thicknesses, materials and exclusions. It sets the price and measures every change.
Sealcoat: A liquid coating of asphalt emulsion or coal tar, mixed with water and sand and applied in thin coats over asphalt to protect it from sun, water and fuel.
Site map: The drawing surface a job's price comes from: an aerial photo of the lot, or a GC's PDF plan sheet, with the areas, lines and counts you trace on it.

Tack coat: A light spray of asphalt emulsion on an existing or milled surface before a new lift of hot mix goes down, so the new lift bonds to the pavement underneath.
Time and materials: Pricing where the customer pays for the actual labor, equipment and material used, at rates set in the contract, for work that couldn't be priced up front.

Unit weight: The weight of a material per cubic foot, used to turn the area and thickness of asphalt, concrete or stone into the tons or yards you order and pay for.

Waste factor: A percentage added to a calculated material quantity to cover what the formula misses on a real job: uneven surfaces, hand work, spillage and leftovers.
Water-cement ratio: The weight of water in a concrete mix divided by the weight of cement. The lower the ratio, the stronger and more durable the concrete, if it can be placed.