The paving field-card pack

Paving

ADA accessible parking layout

• 2010 ADA Standards (Section 208.2) require 1 accessible space per 1 to 25 spaces, scaling up by table; count every space in the facility.
• At least 1 of every 6 accessible spaces, rounded up, must be van-accessible, so the smallest lot's one accessible space is a van space.
• Car accessible space is 8 ft wide with a 5 ft access aisle; van is 11 ft plus 5 ft or 8 ft plus 8 ft, with 98 in vertical clearance.
• Accessible spaces and aisles slope no more than 1:48 (about 2 percent) in all directions; build to 1.5 percent for margin.
• Mount the accessible sign with bottom at least 60 in above the surface; state codes like California require higher, and stricter code wins.

Paving

ADA curb ramp and detectable warning

• Curb ramp running slope holds 8.3 percent (1:12) maximum; cross slope holds 2 percent (1:48) maximum, the number-one rejection.
• Aim for 7 to 7.5 percent running and 1.5 percent cross slope to leave margin before the concrete drifts over the limit.
• Top landing must be at least 4 ft by 4 ft at 2 percent maximum in any direction; gutter counter slope holds 5 percent maximum.
• Detectable warning of truncated domes runs full width, 2 ft deep in direction of travel, at back of curb, with color contrast.
• Bottom transition must be flush: square lip up to 1/4 in, or 1/4 to 1/2 in only if beveled at 1:2 max; check slopes with a digital level before concrete sets.

Paving

Aggregate base and gravel roads

• Use dense-graded angular crushed stone (crusher run / DGA / 21A / 411 / GAB / 3/4 minus), not round pit-run gravel, which rolls, ruts, and washboards.
• Driving-surface gravel commonly runs 8 to 15 percent fines passing the #200 sieve at a low (single-digit) plasticity index; the agency spec sets the band.
• Crown a gravel road steeper than pavement: often around 4 percent (about 1/2 in fall per foot), some agencies 4 to 6 percent; confirm against the spec.
• Compact granular base in controlled lifts (commonly 6 to 8 in compacted) at near-optimum moisture; base density target is commonly 95 percent of modified Proctor.
• Fix washboarding by cutting below the corrugations, restoring moisture and crown, and recompacting; blading only the tops regrows the pattern within days.

Paving

Asphalt compaction and rolling

• Asphalt compaction means rolling the hot mat to target density (low air voids) while the mix stays in its temperature window; density best predicts pavement life.
• Roughly every 1 percent of density below target costs about 10 percent of pavement life.
• Dense-graded hot mix targets about 92 to 96 percent of Gmm (around 4 to 8 percent air voids), with 94 to 95 percent a frequent acceptance point; the JMF and spec set the actual target.
• Rolling runs three phases in order: breakdown (vibratory steel, most density behind the paver), intermediate (pneumatic, kneads in the rest), finish (static steel, removes marks).
• Below the cessation temperature (often around 175 to 185 F for dense-graded mixes) rolling no longer adds density; roll to the measured mat temperature, not a chart.

Paving

Asphalt compaction window

• Cessation (stop) temperature for many dense-graded HMA mixes sits near 175 to 185°F; below it rolling smooths but no longer cuts air voids.
• Breakdown rolling builds most density and should start hot, commonly above ~280°F behind the screed; no downstream roller recovers a lost breakdown pass.
• Common field density target on a dense-graded mat is about 92 to 93% of Gmm (7 to 8% air voids); below ~92% voids interconnect and water gets in.
• Minimum lift thickness runs about 3x NMAS for fine-graded mixes and 4x for coarse, with a working range of roughly 3 to 5x.
• Cores control acceptance; nuclear or PQI gauges are control-only and must be correlated to cores, and when they disagree the core wins.

Codes ASTM D2041, ASTM D2950

Paving

Asphalt density testing

• In-place asphalt density is reported as percent of Gmm; a common field target is 92 to 93 percent of Gmm, about 7 to 8 percent air voids.
• Percent of Gmm equals core bulk specific gravity (Gmb) divided by theoretical maximum (Gmm, the Rice value), times 100; run Gmm on the day's mix.
• Each extra 1 percent of air voids costs roughly 10 percent of pavement service life, per long-standing agency research.
• Cores are the referee and settle acceptance; gauges only estimate density and must be correlated to cores, and the core wins disputes.
• The longitudinal joint is tested and paid separately, often against a minimum near 90 percent of Gmm, because it runs lean and fails first.

Codes ASTM D2041, ASTM D2726, ASTM D2950, ASTM D979

Paving

Asphalt distress and crack diagnosis

• Alligator (fatigue) cracking is interconnected wheelpath cracking from a weak, thin, wet, or uncompacted base; it needs a full-depth patch, not a seal.
• Block cracking is large rectangular blocks across the whole surface from binder shrinkage and aging; seal early, overlay late, never reconstruct the base.
• Sort load from non-load first: wheelpath/loaded-area cracking is structural, while whole-surface cracking regardless of traffic is age and weather.
• Reflective cracking is an old crack printing through a new overlay; remove or relieve the cracks before overlaying, never after.
• Name and rate distress against the FHWA LTPP distress manual and ASTM D6433, with the owner or agency spec setting the thresholds.

Codes ASTM D6433

Paving

Asphalt driveway installation

• A residential asphalt driveway runs 2 to 3 in compacted asphalt mat over 6 to 8 in compacted aggregate base on a proven subgrade.
• The base and drainage decide how long a driveway lasts; the base commonly carries half to two-thirds of the section's strength.
• Grade the surface to drain away from the house at 1 to 2 percent (about 1/8 to 1/4 in per foot); below 1/2 percent it ponds.
• Roll the asphalt to density inside the cooling window, and support every edge with a taper, backfill, and restraint.
• Drive on it in 24 to 72 hours, but wait to first sealcoat until cured, commonly 6 to 12 months and not before 90 days.

Paving

Asphalt mill and overlay

• Mill and overlay grinds off the worn top asphalt with a cold-milling machine, then paves a new lift over a tacked, bonded surface.
• Mill and overlay fits a surface failure over a sound base; alligator cracking or base rutting needs full-depth patching or reconstruction first.
• Tack residual rate runs about 0.05-0.08 gal/sy on milled asphalt versus 0.03-0.05 gal/sy on smooth pavement; let the emulsion break before paving.
• Minimum overlay lift is about 3x NMAS for fine-graded mixes and 4x for coarse, so a 1/2 in mix wants roughly 1.5-2 in compacted.
• Smoothness check: no deviation over about 1/4 in under a 10 ft straightedge, plus an IRI profiler target set by the agency spec.

Codes ASTM D2041, ASTM D2950

Paving

Asphalt milling and cold planing

• Asphalt milling (cold planing) grinds a controlled thickness of pavement with a carbide-toothed drum before overlay; the millings are recycled as RAP.
• A typical mill-and-fill removes the surface course at the overlay thickness, often 1.5 to 2 in; verify depth against the contract and DOT spec.
• Use automatic grade control (stringline, averaging beam, sonic, or 3D) so the drum cuts true profile instead of copying the old wavy surface.
• Sweep and knock down fine dust before tack; a dirty milled surface acts as a bond breaker and the overlay delaminates within a season or two.
• Never leave a sharp vertical drop-off open to live traffic without ramps, signs, and time limits per the traffic-control plan and MUTCD.

Paving

Asphalt mix design (Superpave)

• Superpave mix design targets 4 percent air voids at Ndesign on a chosen PG binder; the agency approves the job mix formula and the field protects it.
• PG binder grade is written high minus low in Celsius (e.g. PG 64-22): climate sets the base grade, slow or heavy traffic bumps the high number up, usually with polymer.
• Ndesign gyrations rise with traffic: 50 for light local roads, 75 for medium collectors, and 100 for highways and heavy traffic.
• TSR (tensile strength ratio, wet over dry) under AASHTO T283 must usually be at least 0.80; below that add anti-strip such as hydrated lime at 1 to 1.5 percent.
• Superpave governs under AASHTO M323 (requirements) and R35 (procedure); minimum lift thickness is three to four times the NMAS, and low VMA cannot be fixed by adding binder.

Paving

Asphalt mix types by layer

• Surface course uses fine 9.5 to 12.5 mm dense-graded mix for a smooth, skid-resistant, watertight top; base uses the largest stone, 25 to 37.5 mm, for structure.
• Compacted lift thickness must be at least three to four times the NMAS, or the stones bridge, the mat tears, and density is unreachable.
• Stone matrix asphalt (SMA) is gap-graded with 70 to 80 percent coarse aggregate, around 6 to 7 percent binder, and about 0.3 percent fiber to resist rutting under heavy slow load.
• Open-graded friction course (OGFC) holds roughly 18 to 22 percent voids to drain water on high-speed roads; it ages faster and clogs on slow routes.
• Dense-graded HMA is the default mix for surface, binder, and base; designed under Superpave (AASHTO M323/R35), with the agency specification controlling mix designations and lift rules.

Paving

Asphalt pavement thickness design

• Asphalt pavement design sets surface, base, and subbase thicknesses from five inputs: traffic (ESALs), subgrade strength, materials, climate, and reliability.
• One ESAL equals one pass of a standard 18,000 lb single axle; pavement damage rises with about the fourth power of axle load, so trucks dominate the design.
• AASHTO 93 produces a structural number (SN), not a thickness: SN = a1D1 + a2D2m2 + a3D3m3, distributed across layers by layer coefficients.
• Common layer coefficients per inch: asphalt concrete about 0.40 to 0.44, crushed aggregate base about 0.11 to 0.17, granular subbase about 0.08 to 0.11.
• Never copy a thickness between jobs; design to the governing agency method and confirm the field subgrade matches the geotech report.

Paving

Asphalt paving estimating

• A paving bid equals takeoff plus unit costs plus overhead and profit; under-estimate and you lose money, over-estimate and you lose the job.
• Convert area to square yards by dividing square feet by 9, since paving is bid and paid in square yards.
• Asphalt tonnage equals area times thickness times density divided by 2000, using about 145 to 150 lb per cubic foot for dense hot mix.
• Add a 5 to 10 percent waste factor to calculated tonnage; the smaller and more cut-up the lot, the higher the factor.
• A 20 percent margin requires a 25 percent markup on cost (markup = margin / (1 - margin)); markup and margin differ.

Paving

Asphalt paving inspection

• Field density target on a dense-graded asphalt mat commonly runs about 92 to 93 percent of Gmm, set by the agency spec.
• Asphalt yield runs roughly 110 lb per square yard for each inch of compacted thickness, so a 2-inch lift is near 220 lb/SY.
• Tack coat must break (water evaporated, color turned black) before the mat covers it, or trapped steam causes a debonding slip plane.
• Most specs require a surface and air minimum near 40 to 50 degrees F for surface courses; the compaction window sets the real limit.
• Probe mat temperature behind the screed, not the truck ticket, because compaction starts from the temperature in the mat.

Codes ASTM D2041, ASTM D2726, ASTM D2950, ASTM D979

Paving

Asphalt paving joints and handwork

• Asphalt joints fail first because the seam's open, unconfined edge spreads under the roller and runs lean, letting water in to ravel and crack.
• A well-built longitudinal joint runs about 2 percent below mat density; a bad one runs 5 to 10 points low.
• Lap the hot lane onto the cold mat about 1 to 1.5 in, tack the cold face, and roll the joint from the hot side.
• End transverse joints on a vertical full-thickness edge, start even to ~1/8 in high, and accept under 1/4 in deviation on a 10 ft straightedge.
• Joint density specs commonly require ~89 to 91 percent of theoretical maximum or ~2 percent below mat; the project and agency spec governs.

Paving

Asphalt plant production

• Hot mix asphalt commonly discharges near 300 to 325 degrees F, but the binder grade and agency spec set the true target, not a fixed number.
• A batch plant weighs and mixes discrete batches in a pugmill for tight control; a drum plant dries and mixes continuously for higher volume and lower cost.
• RAP enters behind the burner flame (mid-drum collar or at the weigh hopper), never through it, because aged binder would smoke and foul the baghouse.
• Warm mix is produced 30 to 100 degrees F cooler via additive or foaming, cutting fuel and aging and allowing higher RAP, but demands thorough drying.
• Pull the plant ticket and QC lot data first when a mat misbehaves; mix reading hot but working tender was often held too long in the silo and oxidized.

Paving

Asphalt recycling and FDR

• RAP (reclaimed asphalt pavement) replaces part of virgin aggregate and binder; most production hot mixes run roughly 10 to 20 percent RAP.
• RAP tiers: up to about 15 percent keeps the same virgin binder grade; 15 to 25 percent drops binder one grade softer; above 25 percent needs blending charts and often a rejuvenator.
• Full-depth reclamation pulverizes the full asphalt section plus underlying base, commonly 6 to 12 inches deep, and stabilizes it into a new base in place.
• FDR stabilizer choice: cement for broad range and most strength, lime for clay-heavy material, asphalt emulsion or foamed asphalt for a flexible bound base.
• Cure the reclaimed base to the spec's strength and moisture target before surfacing; paving early traps moisture and fails the surface. Governing references: ARRA, Asphalt Institute, PCA, AASHTO R 35 and M 323.

Codes ASTM D2172

Paving

Asphalt segregation

• Asphalt segregation is non-uniform aggregate gradation (physical) or temperature (thermal) in the mat, leaving high-void spots that ravel, crack, and pothole years early.
• Physical (gradation) segregation cannot be compacted out, since the missing fine material and binder cannot be added with a roller; the spot is removed or lived with.
• Thermal differential break points often run near 25°F for moderate and above roughly 50°F for severe, but the DOT or project spec and mix set the actual limit.
• Keep the paver hopper at least a third full, never run it empty, and never fold the wings onto empty conveyor slats, or a cold coarse gob feeds through.
• Load trucks in two to three drops (not one pile), add an MTV on segregation-prone mixes and long hauls, and use the IR bar plus density to catch and prove cold spots.

Paving

Asphalt vs concrete pavement

• No single winner exists between asphalt and concrete; the load, climate, budget, timeline, and life-cycle cost decide each job.
• Concrete commonly lasts 30 to 40 years; asphalt commonly runs 15 to 20 years with periodic resurfacing.
• Asphalt is almost always cheaper to build per square yard, but compare life-cycle cost over a common period, not first cost.
• Use concrete for heavy, slow, turning, or standing loads and where fuel, oil, or sustained heat is present (dock aprons, bus pads, fueling lanes).
• Asphalt opens to traffic in hours after cooling below roughly 100 F; concrete needs days of curing, with FHWA LCCA using at least a 35-year analysis period.

Codes ACI 330

Paving

Chip seal surface treatment

• A chip seal sprays asphalt binder, covers it immediately with stone chips, then rolls them in to seal sound pavement; it adds no structure and repairs no failed road.
• Chip embedment targets 50 to 70 percent of stone height after rolling (AASHTO cites about 50 to 60 percent); too shallow sweeps off, too deep bleeds.
• Use pneumatic rubber-tire rollers, never steel drum, which bridges and crushes chips and leaves them unseated.
• No chip seal below about 50 degrees Fahrenheit air or pavement, or if forecast to drop below during cure; the surface must be dry and rain is a hard stop.
• A single chip seal commonly lasts 5 to 7 years; binder and chip rates are design numbers set by the project and DOT spec, verified every section.

Paving

Cold-weather asphalt paving

• Minimum paving temperature is set by the spec, not a universal number; a common surface-course line is 40 to 50F air and surface, and rising.
• Thin lifts (1 in or less) often require ~50F and rising; thick base lifts (3 in+) are sometimes allowed into the 30s F because more mass holds heat longer.
• Never pave on a frozen or saturated base: melting ice softens the subgrade and the pavement settles and cracks; frost, standing water, or pumping soil is a hard stop.
• Field density target on a dense-graded mat is roughly 92 to 93 percent of Gmm (7 to 8 percent air voids); below ~92 percent voids interconnect and the mat ravels and cracks early.
• Read base and surface temperature with an infrared gun where you pave, not just the air, and confirm the spec, cutoff date, and warm-mix allowance with the agency (AHJ).

Codes ASTM D2041, ASTM D2950

Paving

Concrete curb, gutter, and sidewalk

• Accessible sidewalk cross slope is held to 1:48 (about 2 percent) and curb ramp running slope to 1:12 maximum (about 8.3 percent).
• Curb and gutter flow line needs positive longitudinal grade to an inlet, commonly a minimum near 0.4 to 0.5 percent, with no sag or reverse.
• Exterior flatwork in freeze country commonly specifies 4000 psi at 28 days and 5 to 7.5 percent entrained air, verified on the truck.
• Never finish concrete while bleed water is on the surface; doing so seals a weak layer that dusts, scales, and crazes.
• Sidewalk contraction joints are commonly spaced about the walk width; isolation joints go at the building, curb, and every fixed object.

Codes ACI 302, ACI 318, ACI 330

Paving

Concrete pavement jointing and curing

• Saw contraction joints to one quarter to one third of slab depth (D/4 to D/3); early-entry saws cut shallower, often near 1 in on slabs up to 9 in.
• Saw timing: conventional wet saw about 4 to 12 hours after placement, early-entry (green) saw about 1 to 4 hours, before random cracking starts.
• Space contraction joints at roughly 24 to 36 times slab thickness (2 to 3 ft per inch); keep panels under 1.5 to 1 length-to-width.
• Dowels are smooth, cross transverse joints, transfer load and slide; tie bars are deformed, cross longitudinal joints, hold lanes together and do not slide.
• Cure with white-pigmented ASTM C309 liquid membrane compound right behind texture, about 1 gallon per 200 sq ft, two coats on tined surfaces; open to traffic on measured strength (often 350 to 450 psi flexural), not the calendar.

Codes ASTM C1074, ASTM C309, ASTM C39, ACI 325, ACI 330

Paving

Concrete pavement types

• Rigid concrete pavement has three families: JPCP (no slab steel, joints near 15 ft), JRCP (light steel, joints 30 ft or more), and CRCP (heavy continuous steel, no transverse joints).
• JPCP carries no slab steel, only smooth dowels for load transfer across transverse joints and deformed tie bars to hold longitudinal joints; dowels and tie bars are not interchangeable.
• CRCP is designed to crack every 3 to 6 ft in tight hairlines the continuous steel (around 0.6 to 0.8 percent) holds shut, transferring load by aggregate interlock.
• Faulting comes from lost load transfer plus water pumping fines out under the slab edge; dowel bar retrofit restores load transfer and can add 10 to 15 years.
• Slab thickness and pavement type come from a structural design (traffic, k-value support, flexural strength via AASHTO or Pavement ME), not a field rule of thumb.

Codes ACI 325, ACI 330

Paving

DOT compliance for contractors

• A truck or combination rated 10,001 lb GVWR/GCWR or more in interstate commerce is a commercial motor vehicle needing a USDOT number.
• A CDL is required at 26,001 lb GVWR single vehicle, or 26,001 lb combination with a trailer over 10,000 lb, or any placardable hazmat load.
• An expired DOT medical card makes the driver not qualified and out of service; the card is valid up to 24 months, sometimes less.
• The short-haul exemption covers drivers within a 150 air-mile radius released within 14 hours, who keep timecards at least 6 months instead of logs.
• Property-carrying hours of service caps driving at 11 hours after 10 hours off, inside a 14-hour window, with a weekly 60-in-7 or 70-in-8 limit.

Paving

Fleet maintenance program

• Service heavy equipment on the OEM interval by running hours, typically at 250, 500, 1,000, and 2,000 hours, never by waiting for failure.
• Hard, dusty, or high-load service shortens the recommended interval by 20 to 30 percent; when in doubt, service earlier, never later.
• A DVIR (driver vehicle inspection report) is required under 49 CFR 396.11 when a defect is found; carriers retain it at least 3 months.
• Commercial trucks need a periodic inspection at least every 12 months under 49 CFR 396.17; documentation is kept for 14 months.
• Owning and operating cost equals fixed owning cost plus variable operating cost divided by hours worked; fuel often runs 30 to 50 percent of operating cost.

Paving

Fog seal and rejuvenator preservation

• A fog seal is a light spray of diluted asphalt emulsion that seals the surface, binds early raveling, and slows oxidation on sound pavement.
• An asphalt rejuvenator penetrates and restores the aged binder by replacing lost maltenes, softening brittle asphalt and bringing back flexibility.
• Fog seals and rejuvenators preserve good pavement only; they do not fix rutting, alligator cracking, potholes, or structural failure.
• Diluted fog seal application rate commonly lands near 0.05 to 0.15 gal/SY, emulsion often diluted about 1 part water to 1 part emulsion; confirm against the data sheet and spec.
• Friction loss is the number one risk; hold traffic until the surface turns black, stops tracking, and friction returns, and keep sand on hand to blot rich areas.

Codes ASTM D2995, ASTM D6433

Paving

Geotextile separation fabric

• Separation is the geotextile's main job: a fabric between soft subgrade and aggregate keeps stone from punching down and fines from pumping up.
• Recommend separation where the subgrade carries more than roughly 10 to 15 percent fines or has a low CBR under heavy or repeated load.
• AASHTO M288 separation applies to unsaturated subgrades around CBR 3 and up; softer or saturated soils move to the stabilization application.
• M288 grades survivability into Class 1 (toughest, most severe), Class 2, and Class 3 (lightest, roughly 50 to 60 percent of Class 1 strength).
• Never drive on bare fabric: end-dump aggregate onto placed stone and push it forward so equipment always rides on stone, not cloth.

Paving

Grade control and machine control

• Grade control sets and holds design elevations, slopes, and smoothness, deciding drainage, layer thickness and yield, and ride.
• GNSS RTK machine control typically holds horizontal near 10 mm and vertical near 15 to 20 mm, not tight enough for fine grade or the wearing surface.
• Robotic total station (UTS) gives millimeter-class position, commonly 3 to 5 mm vertical, the accuracy the paver, fine-grade trimmer, and mill need.
• Cross-slope around 2 percent is common on roads and lots, but the plan and agency spec set the number; flat or reversed slope ponds water.
• Always check grade and cross-slope behind the machine with a rod and smart level; the systematic error that reads consistent costs the most.

Paving

Intelligent compaction for asphalt

• Intelligent compaction rolls asphalt with a vibratory roller carrying GPS, a drum accelerometer, and an infrared temperature sensor, mapping pass count, mat temperature, and stiffness live.
• ICMV (intelligent compaction measurement value) is relative stiffness, not density; values vary by manufacturer (CMV, Evib, branded index) and do not transfer between machines.
• IC supplements core and gauge density acceptance, it does not replace it; final-pass ICMV correlates poorly with core density, so cores still accept the work.
• IC measures 100 percent of the mat it rolls versus a handful of cores, exposing cold streaks, missed passes, and soft support spots while the mat is still workable.
• Framework is the FHWA IC program and AASHTO standard practice (cited as AASHTO PP81 for soils); confirm current designation and project spec, since standards get renumbered.

Paving

Longitudinal joint density

• Longitudinal joint density is the in-place density of the seam between two adjacent paving passes, almost always the lowest-density, most permeable line on the job.
• Joint density specs commonly require a minimum around 91 percent of Gmm, or a differential limit of about 2 percent (roughly 3 lb/ft3) below the adjoining mat.
• Most joint density is won on the first pass: confine the unconfined edge while it is hot, before the second lane is even laid.
• Roll the joint from the hot side, keeping the drum about 6 in inside the hot lane first, then overlapping the cold side about 6 in to pinch the seam.
• Always tack the cold vertical joint face before paving against it, and stagger joints about 6 in between lifts so lean seams do not stack.

Paving

Pavement base and subgrade compaction

• Aggregate base is commonly compacted to 95 percent of modified Proctor maximum dry density near optimum moisture; subgrade top often 95 percent, deeper fill about 90 percent.
• The project geotechnical report and earthwork specification set the actual targets and name which Proctor governs, so confirm before rolling, never assume.
• Modified Proctor (ASTM D1557) uses roughly 4.5 times the energy of standard Proctor (ASTM D698), giving higher density at lower optimum moisture.
• Proof rolling drives a heavy loaded vehicle, often a 20 ton tandem dump truck, slowly over the surface to reveal soft areas by pumping and rutting.
• The accepted base is a hold point: do not pave until density tests and proof roll pass and are documented, because buried defects are expensive.

Codes ASTM D1556, ASTM D1557, ASTM D6938, ASTM D698

Paving

Pavement condition assessment (PCI)

• The Pavement Condition Index (PCI) rates asphalt surface condition 0 to 100 under ASTM D6433, where 100 is no visible distress and 0 is failed.
• Score every distress on three columns: type, severity (low, medium, high), and extent (density against the sample area); miss one and the PCI is wrong.
• Alligator cracking and rutting are load/structural failures needing base repair; block cracking and raveling are climate/age failures needing preservation.
• Never overlay alligator cracking; the bad base reflects the crack pattern back through the new mat within a season or two, so patch full-depth first.
• The first 40 percent drop in quality takes about 75 percent of pavement life; a dollar of preservation up the curve does the work of 6 to 10 dollars of rehab.

Codes ASTM D5340, ASTM D6433

Paving

Pavement marking and striping

• New asphalt needs roughly 30 days to cure before permanent striping (some references allow 14); lay temporary solvent paint first, then permanent.
• Stripe only on a clean, dry, fully cured surface; do not apply below about 40F, above 85 percent humidity, or within 5F of the dew point.
• Waterborne paint lasts about 1 to 2 years; thermoplastic runs roughly 4 to 6 times longer, up to about 8 years.
• Glass beads give night retroreflectivity; the MUTCD requires night-visible markings to be retroreflective, and a line without beads goes dark after dusk.
• Under the MUTCD, white separates same-direction traffic and marks stalls, yellow separates opposing traffic, red prohibits entry, blue supplements accessible parking.

Paving

Pavement marking materials and application

• Waterborne paint goes on at about 15 mils wet, dries to roughly 9 mils, no-track in under 10 minutes, and lasts 1 to 2 years.
• Thermoplastic is melted to around 400F, laid 90 to 125 mils thick, and lasts 3 to 5 years under traffic.
• Glass beads provide retroreflectivity; drop-on rate for waterborne paint commonly runs about 6 pounds per gallon, up to 12.
• MUTCD maintained retroreflectivity minimums are commonly cited as 50 mcd/m2/lux at 35 mph and up, 100 on highest-speed roads.
• Stripe new asphalt only after roughly 30 days of cure, with pavement and air at least 50F and rising on a clean, dry surface.

Paving

Pavement preservation treatments

• Pavement preservation applies low-cost treatments to still-sound pavement to delay reconstruction; it adds little or no structure and cannot rescue a failed road.
• The first 40 percent drop in pavement quality takes about 75 percent of its life; the next 40 percent drop takes only about 12 percent.
• Preservation returns roughly 6 to 10 dollars of avoided rehab or reconstruction per dollar spent at the right point in the curve.
• No preservation treatment fixes alligator cracking or base failure; structural distress vetoes every treatment regardless of the PCI score.
• Apply emulsion and sealcoat work at surface and air temperature of at least 50 degrees F and rising, dry, with cure time before traffic.

Codes ASTM D6433, ASTM D6690

Paving

Pavement subdrains and edge drains

• An edge drain is a perforated pipe in a geotextile-wrapped aggregate trench along the pavement edge, sloped to daylighted outlets.
• Outlets are where edge drains die: a blocked or missing outlet backs water against the pavement, which is worse than no drain at all.
• Pipe size, outlet spacing, and filter gradation come from the agency or DOT subdrainage standard, not a rule of thumb.
• Agencies commonly set a minimum pipe diameter near 4 in so the line can be jetted and cleaned later.
• Pumping needs water, fines, and load together; remove the free water with a drain and the void-forming mechanism stops.

Paving

Permeable pavement install

• Permeable pavement is a stormwater reservoir you drive on, so protect the uncompacted subgrade instead of rolling it tight; a tighter section is a worse section.
• Reservoir stone must be washed, angular, open-graded; open-graded stone holds roughly 40 percent void, so about a foot of No. 57 stone stores roughly 4.8 inches of water.
• Roll porous asphalt just 2 to 3 static steel-wheel passes to seat the mat, then stop; no vibratory or rubber-tire roller, which closes surface voids.
• Cover pervious concrete with plastic within about 20 minutes and keep it moist for the cure period, often about 7 days with no traffic.
• Prove drainage at handoff with a surface infiltration test: ASTM C1701 for porous asphalt and pervious concrete, ASTM C1781 for PICP.

Codes ASTM C1701, ASTM C1781, ACI 522

Paving

Porous and permeable pavement

• Permeable pavement (porous asphalt, pervious concrete, or PICP) passes rain through the surface into an open-graded stone reservoir that infiltrates the soil instead of running off.
• Never compact or proof-roll the infiltrating subgrade; rolling it to 95 percent density seals the floor of the system and the whole section fails.
• Reservoir stone must be clean, open-graded, single-sized and washed free of fines; fines clog the voids and destroy storage and drainage.
• Clogging from sediment is the number one failure mode; regular vacuum sweeping is mandatory, and no sand, sealcoat, or dense-mix patching, all of which seal the pores.
• Surface infiltration is the acceptance test, not density: ASTM C1701 for pervious concrete and porous asphalt, ASTM C1781 for permeable pavers.

Codes ASTM C1701, ASTM C1781, ACI 522

Paving

Pothole patching and asphalt repair

• A lasting pothole patch squares the hole to sound pavement, dries it, tacks the edges, fills in compacted lifts, and seals the perimeter joint.
• Place fill in lifts of about 2 in (50 mm) or less and compact each lift before the next; a deep dump cannot compact to the bottom.
• Hot mix asphalt lasts 10 to 15 years placed hot and compacted; bagged cold patch lasts one to two seasons and is for emergencies and winter.
• A surface patch over a wet or failed base fails again; correct the base and drainage with a full-depth repair when the base is gone.
• The FHWA documents four methods (throw-and-roll, semi-permanent, spray injection, edge seal); SHRP found material quality matters more than method.

Paving

Proximity warning and struck-by safety tech

• Struck-by is one of OSHA's construction Focus Four, and roughly three out of four struck-by fatalities involve heavy equipment, most often backing or turning.
• Separate people from equipment first with an internal traffic control plan, spotter, and high-vis; proximity warning, camera, and radar are the last layer.
• If the operator cannot see the spotter, the machine does not move; the spotter is the control and the tech is the backup.
• Alarm fatigue is the single biggest reason proximity tech fails; fix it by tuning the detection zone, not by muting or disabling the system.
• Tag-only systems miss the untagged visitor, dead battery, or tag left in the truck; cameras and radar see whatever is there, tagged or not.

Paving

Sealcoat and crack seal maintenance

• Crack seal working cracks that move more than about 1/8 in with flexible hot-pour sealant; fill non-working cracks with stiffer asphalt emulsion.
• Never seal or coat alligator cracking; it is base fatigue failure that needs full-depth patching, then preserve sound pavement around it.
• Apply sealcoat as two thin coats at roughly 0.15 to 0.22 gallons per square yard total; two thin coats outlast one heavy coat.
• Sealcoat needs at least 50F surface and air temperature, no rain about 24 hours before and after, 24 hours before foot traffic, 48 before vehicles.
• Run the lot sequence crack seal, patch, sealcoat, stripe; rate condition with PCI (0 to 100, ASTM D6433) where above about 70 is preservation territory.

Codes ASTM D6433, ASTM D6690

Paving

Slurry seal and micro-surfacing

• Slurry seal cures by water evaporation and needs warm dry weather; micro-surfacing uses polymer-modified emulsion that sets chemically regardless of weather.
• Micro-surfacing reopens to traffic in about an hour and can fill wheelpath ruts past about 1/2 in with a rut box; slurry seal cannot.
• Slurry seal commonly adds 5 to 7 years and micro-surfacing 6 to 8 years, but only on a structurally sound, surface-distressed pavement.
• Slurry follows ISSA A105 / ASTM D3910; micro follows ISSA A143 / ASTM D6372, with the project spec and approved mix design governing.
• Crack seal working cracks and full-depth patch failed or alligatored sections before treating; neither treatment adds structure or fixes a base failure.

Codes ASTM D3910, ASTM D6372

Paving

Striping layout and stall geometry

• A standard parking stall is commonly 9 ft wide by 18 ft deep, about 162 sq ft, with the local zoning code setting the minimum.
• A two-way drive aisle for 90-degree parking is commonly 24 ft wide; fire apparatus access roads need at least 20 ft, often 26 ft.
• The 2010 ADA Standards set accessible counts by lot size (1 to 25 spaces needs 1), and at least 1 of every 6 accessible spaces must be van-accessible.
• Accessible spaces and access aisles cannot exceed 1:48 slope, about 2.08 percent, in any direction under the ADA Standards.
• Wait roughly 30 days for new asphalt to cure before a permanent stripe, or lay a temporary coat and return after curing.

Paving

Subgrade stabilization

• Match the binder to the soil: lime for wet, high-PI plastic clay, cement for granular and low-plasticity silty soil.
• A proof roll drives a loaded tandem-axle dump truck slowly across the subgrade; rutting, sustained deflection, or pumping flags a fail.
• Add the additive rate the lab mix design sets for the actual site soil, never a guessed or remembered number from another job.
• Lime-treated plastic clay mellows roughly 24 to 72 hours kept moist before final mixing and compaction so lime reacts through the clods.
• Re-proof roll the treated subgrade after cure and confirm no rutting or pumping before any aggregate base goes down.

Codes ASTM D6276

Paving

Tack and prime coat

• Tack coat bonds new asphalt to the asphalt layer below; prime coat soaks into a granular base to bind and seal it for the first asphalt layer.
• Residual rate, not applied rate, is what specs set: roughly 0.02 to 0.05 gal/sq yd on new tight asphalt, 0.04 to 0.07 on oxidized, 0.06 to 0.08 on milled surfaces.
• Do not pave until the emulsion breaks fully black; laying hot mix on brown, unbroken tack traps water and gives almost no bond.
• Tack bonds to whatever is on the surface, so sweep and blow dust, milling fines, and moisture clean and dry before spraying.
• Slippage cracking (crescent cracks) and delamination at the bond line are tack failures, not mix or thickness problems, and the project specification is the controlling rate authority.

Paving

Utility locating and call before you dig

• Call 811, your state one-call center, before any excavation; the call is free and required by law in every state.
• Call several business days ahead, commonly two to three, and start only after every notified utility posts a positive response.
• APWA color code: red electric, yellow gas/oil, orange communication/fiber, blue potable water, green sewer, purple reclaimed water, pink survey, white proposed dig.
• Hand-dig or vacuum-excavate the tolerance zone, commonly 18 to 24 inches each side of a mark, keeping machines out until the line is exposed.
• 811 marks only utility-owned lines up to the meter; hire a private locator for customer-side lines like irrigation, site lighting, and propane.

Codes 29 CFR 1926

Paving

Warm mix asphalt (WMA)

• Warm mix asphalt (WMA) is the same mix produced and placed roughly 30 to 100°F cooler than hot mix, keeping aggregate, gradation, and binder grade unchanged.
• Hot mix runs commonly 300 to 350°F; warm mix typically lands around 215 to 290°F, with the design and agency spec setting the target.
• WMA is made three ways: foaming (water injection), chemical additives (Evotherm, Rediset), or organic wax (Sasobit); the plant and mix design pick one.
• Lower heat leaves less margin to dry the aggregate, so trapped moisture can strip the binder; anti-strip and a TSR check under AASHTO T283 are required, with a minimum TSR around 80 percent commonly used.
• Density target is unchanged: still commonly around 92 to 93 percent of Gmm, measured the same way, with cores controlling acceptance over the gauge.

Codes ASTM D2041, ASTM D2950