Highway Joint Sealants: Cold vs Hot vs Preformed
Choosing between cold-applied silicone (ASTM D5893), hot-applied rubberized asphalt (ASTM D6690), and preformed compression seals (AASHTO M 220) for PCC pavement joints and crack sealing
Last updated: April 19, 2026
Overview
Highway joint sealants do one job: keep water and incompressibles out of pavement joints and cracks so the slab edges stay intact and the subgrade stays dry. When the sealant fails, water gets under the slab, fines pump out, voids form, and within a few freeze-thaw cycles the joint spalls. Replacing a sealant is cheap; replacing a slab panel is not.
Three product families dominate Portland Cement Concrete (PCC) pavement work: cold-applied single-component silicone covered by ASTM D5893, hot-applied rubberized asphalt covered by ASTM D6690, and preformed polychloroprene compression seals covered by AASHTO M 220. Each one solves a different combination of joint width, traffic, climate, and crew capability.
This guide compares the three families on the criteria that actually drive selection in the field, then walks through the equipment, lifecycle, and DOT spec language that turns a material choice into a buildable project. The framing is intentionally brand-neutral — the same D5893 silicone behaves the same way in a TxDOT joint as it does in a Caltrans joint, regardless of who pumped it.
PCC pavement joints vs bridge deck joints
Both surfaces look like concrete with a gap in it, but the design problem is different and the products are different. Get the framing right before you pick a material.
| Attribute | PCC pavement joint | Bridge deck joint |
|---|---|---|
| Movement source | Slab thermal + drying shrinkage; small per-joint range | Girder thermal + live load rotation + creep; large range |
| Typical joint width | 3/8 in to 1 in (saw-cut transverse and longitudinal) | 1 in to 12+ in across full deck width |
| Typical movement | 1/16 in to 1/4 in per joint | 1/2 in to 4+ in per joint |
| Primary product family | D5893 silicone, D6690 hot-pour, M 220 compression seal | Strip seal, modular (MBEJ), finger plate, APJ, M 297 compression seal |
| Governing standards | ASTM D5893, ASTM D6690, AASHTO M 220, FHWA Pavement Preservation Compendium | AASHTO LRFD §20, AASHTO M 297, NCHRP 467 |
Rule of thumb: if the joint movement is under about a half inch and the joint was saw-cut into a continuous slab, you are in pavement sealant territory and this guide applies. If the joint moves more than a half inch, has a steel edge rail, or sits at an abutment or pier, it is a bridge expansion joint and a different system catalog applies.
Cold-applied silicone (ASTM D5893)
ASTM D5893 covers single-component, cold-applied silicone joint sealants formulated for PCC pavement. The standard recognizes two types: Type I self-leveling (poured into horizontal joints) and Type II non-sag (gun-applied to vertical or sloped joints, less common in pavement work). Both cure by reaction with atmospheric moisture.
Where it wins
- Long service life in moderate-to-cold climates — silicone resists UV and stays elastic over wider temperature swings than rubberized asphalt
- No kettle, no torch, no hot-work permit — single-component silicone applies straight from the pail or drum at ambient temperature
- Wide joint movement capability relative to width — most D5893 silicones rate ±50 percent or higher, easily covering routine PCC joint movement
- Lower long-term incompressibles intrusion because silicone holds bond to clean, dry concrete faces longer than hot-pour rubberized asphalt
- Faster traffic-opening times in cool weather — typical D5893 silicones tack-free in 30 to 90 minutes and traffic-ready within hours
Where it loses
- Higher unit material cost than hot-pour — typically 2 to 4 times the per-foot material cost depending on bead size
- Surface must be dry, clean, and dust-free — silicone will not bond to damp or contaminated concrete, and joint prep equipment must be on-site
- Sensitive to substrate alkalinity and curing-compound residue; some D5893 products require a primer per the manufacturer data sheet
- Not appropriate for asphalt-pavement crack sealing — silicone bond to asphalt is unreliable; use D6690 there
Joint design: D5893 silicones perform best with a backer rod installed to set the recess depth (typically 1/4 to 3/8 in below surface) and to prevent three-sided adhesion. The width-to-depth ratio should be roughly 2:1 — for example, a 3/8 in wide joint takes a 3/16 in deep sealant bead.
For the full standard breakdown including Type I/II differences, performance requirements, and common spec language, see our ASTM D5893 reference page.
Hot-applied rubberized asphalt (ASTM D6690)
ASTM D6690 is the consolidated standard for hot-applied joint and crack sealants used on PCC and asphalt pavements. It replaced and harmonized several legacy AASHTO and federal specs (M 301, SS-S-164, SS-S-1401) and breaks the product family into four types covering progressively more demanding service conditions.
| Type | Service condition | Typical use |
|---|---|---|
| Type I | Standard climates, moderate movement | General PCC and asphalt joint and crack sealing |
| Type II | Lower-temperature flexibility | Northern-tier pavements, longer winters |
| Type III | Higher temperature stability | Hotter climates, heavier traffic |
| Type IV | Jet-fuel and oil resistant | Airfield pavements, fueling areas |
Where it wins
- Lower per-foot material cost than silicone — usually the cheapest sealant option for routine pavement joint and crack work
- Forgiving on substrate moisture — hot-pour drives off surface moisture during placement, so a slightly damp joint is workable where silicone would fail
- Bonds to both PCC and asphalt — the same Type I or II material can seal saw-cut concrete joints and route-and-seal asphalt cracks on the same project
- Fast production rate — a two-person kettle crew can place 1,000 to 3,000 linear feet per shift depending on joint geometry and access
Where it loses
- Shorter service life than silicone — typical 3 to 8 years vs 8 to 15 years for D5893 in the same joint
- Requires a kettle (oil-jacketed melter), torch, hot-work permit, and trained crew — capital and safety overhead silicone work avoids
- Application temperature is critical — overheating breaks the polymer chain and the sealant loses elasticity; underheating means poor bond and tracking
- UV degradation and oxidation over time leave the surface brittle, especially in hot, sunny climates
- Tracking under traffic in hot weather if opened too soon — typical opening times range from 30 minutes to several hours depending on type and ambient temperature
Kettle temperature matters: every D6690 product publishes a safe heating temperature range and a maximum pour temperature. Exceeding the safe heating temperature for even a short period permanently degrades the polymer. A digital kettle thermometer (not just the analog dial) is the single highest-value piece of QC equipment on a hot-pour crew.
For Type I–IV performance requirements, application temperature limits, and common spec language, see our ASTM D6690 reference page.
Preformed compression seals (AASHTO M 220)
AASHTO M 220 covers preformed polychloroprene (neoprene) compression joint seals for concrete pavements. Unlike poured sealants, the M 220 seal is an extruded multi-cell elastomer profile sized to be wider than the joint and held in place purely by lateral compression against the joint walls, assisted by a lubricant-adhesive applied at installation.
Where it wins
- Longest service life of the three families when sized correctly — 15 to 25+ years is realistic
- No on-site curing, kettle, or weather window — the seal is installed in its final state and is traffic-ready as soon as the lubricant flashes off
- Performs predictably in the cold because compression force comes from elastomer rebound, not from a cured chemistry that stiffens at low temperature
- Resists incompressibles intrusion — the seal occupies the full joint width with no recess for stones to lodge in
Where it loses
- Joint width must be controlled tightly — the seal works only inside a defined compression range, typically 80 percent to 50 percent of uncompressed width, so saw-cut tolerance matters
- Higher up-front material cost than hot-pour, sometimes higher than silicone for narrow joints
- Limited movement range per profile — if the joint can move outside the seal compression range, the seal will extrude or pull free
- Repair means replacement, not patching — a damaged section gets pulled and a new piece installed with butt joints sealed
M 220 vs M 297: AASHTO M 220 covers preformed compression seals for concrete pavement joints. AASHTO M 297 covers preformed polychloroprene compression seals for bridge deck joints. Different material requirements, different sizing tables, different test methods. They are not interchangeable — a pavement spec calls M 220, a bridge spec calls M 297.
Crack sealing vs joint sealing
The terms get used interchangeably in casual conversation, but the FHWA Pavement Preservation Compendium and most state DOTs treat them as separate treatments with separate pay items, separate prep, and different success criteria. Mixing them up burns money and shortens service life.
| Attribute | Joint sealing | Crack sealing |
|---|---|---|
| Where it goes | Engineered, saw-cut joints in PCC pavement | Working cracks in asphalt pavement (typically routed first) |
| Geometry | Defined width, depth, and recess via reservoir cut | Variable width; routed to a uniform reservoir 3/4 in × 3/4 in or similar |
| Common products | D5893 silicone, D6690 hot-pour, M 220 preformed | D6690 hot-pour (overband or flush fill) |
| Timing | Concurrent with paving or scheduled maintenance cycle | Before water intrusion has caused subgrade damage; spring or fall |
| Goal | Keep the engineered joint working as designed | Stop water before the crack becomes a pothole |
Crack filling (a third term) is a lower-cost treatment that places sealant into non-working cracks without routing. It buys time on aging asphalt but is not a substitute for true crack sealing where the cracks are moving seasonally.
Application equipment and crew sizing
The equipment list and crew size shift dramatically across the three families. Budgeting a project on per-foot material cost alone misses the bigger driver — labor and equipment hours per linear foot installed.
| Family | Core equipment | Typical crew | Production (lf/shift) |
|---|---|---|---|
| D5893 silicone | Air compressor, sandblaster or wirebrush, vacuum, backer rod tool, bulk pump or pail gun | 2 to 4 (prep + applicator + flagger) | 800 to 2,000 |
| D6690 hot-pour | Oil-jacketed kettle (typically 200 to 410 gal), torch wand, router for cracks, vacuum, hot-work setup | 3 to 5 (kettle operator + applicator + prep + flagger) | 1,000 to 3,000 |
| M 220 preformed | Joint cleaning equipment, lubricant-adhesive applicator, machine seal installer or hand insertion tools | 3 to 4 (prep + installer + helper + flagger) | 500 to 1,500 |
Joint prep is not optional: regardless of family, the universal failure mode is bond loss from contaminated joint walls. Sandblasting or high-pressure waterblasting followed by compressed-air blowout (oil-free) is the baseline. Skipping prep to chase production numbers shortens every product's service life by half or more.
Lifecycle, failure modes, and repair triggers
Service life numbers vary by climate, traffic, joint geometry, and installation quality, but the FHWA Pavement Preservation Compendium and decades of state DOT performance data converge on the ranges below.
| Family | Typical service life | Dominant failure mode | Repair trigger |
|---|---|---|---|
| D5893 silicone | 8 to 15 years | Adhesive failure at joint wall (contamination or movement exceeded) | >10% of joint length showing daylight to backer rod |
| D6690 hot-pour | 3 to 8 years | Surface oxidation, cohesive splitting, tracking under traffic | >15% of joint length showing splits or missing material |
| M 220 preformed | 15 to 25+ years | Compression set, seal pullout from oversized joint, abrasion | Seal recessed below pavement surface or visibly displaced |
What failure looks like in the field
- Adhesive failure: sealant pulls cleanly from the joint wall — substrate prep was insufficient or the joint moved beyond the product class
- Cohesive failure: sealant tears down its own middle but stays bonded to both walls — joint movement exceeded the product movement capability
- Spalling adjacent to the joint: water and incompressibles got under the sealant and the slab edge fractured under load — the failure is now structural, not just sealant
- Pumping and faulting at transverse joints: the deepest signal that the sealant has been failed for years and the subgrade is washing out
Resealing reset: when you reseal a joint, you must remove all old sealant, re-saw the reservoir to a clean profile, blow out, and reinstall backer rod. Pouring fresh sealant over old residue is the most common reason a reseal fails inside two years.
State DOT spec variation
ASTM D5893, ASTM D6690, and AASHTO M 220 are national-baseline standards. State DOTs layer additional requirements — preferred types, climate-specific polymer modifications, qualified product lists, kettle temperature limits, and approved installer programs — on top of the baseline. Always pull the current standard specification from the contracting DOT before final selection.
| State | Common spec posture | Notes |
|---|---|---|
| Caltrans | Standard Specifications Section 41 covers PCC pavement; D5893 silicone is widely used on freeway joint reseal contracts | Climate-driven preference for silicone in coastal and central valley zones |
| TxDOT | Item 438 (Cleaning and Sealing Joints and Cracks) recognizes both hot-applied and cold-applied; DMS-6310 and DMS-6320 cover material qualification | Hot-pour widely used for crack sealing; silicone for high-priority PCC joint reseal |
| FDOT | Section 932 covers joint sealants; both hot-applied and silicone qualified product lists maintained | Type IV jet-fuel-resistant D6690 used at airfield-adjacent work |
| Northern-tier (MnDOT, WisDOT, MDOT) | Strong silicone preference on PCC for cold-weather elasticity; D6690 Type II for crack sealing | Long winters punish hot-pour service life; silicone payback is faster |
The summary above is illustrative, not a substitute for the contracting agency's current spec book and qualified product list. Item numbers, section references, and material qualification programs change between spec book editions; verify against the controlling document on every project.
For broader context on how elastomeric joint sealants are classified outside the highway world, see ASTM C920, the building-envelope counterpart standard. C920 governs vertical wall and glazing joint sealants and uses a different Type/Grade/Class/Use vocabulary than the pavement standards covered here.
Sourcing highway pavement sealants?
We work with US-based distributors of D5893 silicone, D6690 hot-applied rubberized asphalt, and AASHTO M 220 preformed compression seals for state and municipal pavement maintenance contracts. Email partnerships@usmadesupply.com with project type, lane miles or linear feet estimate, and Buy America requirements for sourcing and quote support.
Frequently Asked Questions
What is the difference between ASTM D5893 and D6690?
D5893 covers cold-applied single-component silicone joint sealants for PCC pavement. D6690 covers hot-applied rubberized asphalt joint and crack sealants for both PCC and asphalt pavement. They are different chemistries with different application equipment, different cost profiles, and different service lives. Silicone tends to last 8 to 15 years; hot-applied tends to last 3 to 8 years in the same joint, but at much lower per-foot material cost and with a faster crew production rate.
How long does cold-applied silicone last in a transverse joint vs hot-applied?
In well-prepped transverse PCC joints, D5893 silicone routinely delivers 8 to 15 years before resealing is needed. D6690 hot-applied rubberized asphalt typically delivers 3 to 8 years in the same joint geometry, with shorter life in hot, sunny climates due to UV oxidation and longer life in cool, dry northern-tier conditions. Joint prep quality is the single largest variable for both — a poorly prepped silicone joint will fail faster than a well-prepped hot-pour.
When does a state DOT require preformed compression seals over poured sealants?
Preformed AASHTO M 220 compression seals get specified when the agency wants the longest service life on a high-traffic PCC pavement and the joint geometry can be controlled tightly enough for the seal to stay in its compression range. Common triggers include long-life pavement designs, heavy truck routes, and reconstruction projects where the saw-cut tolerance can be held to spec. They are less common on reseal contracts because existing joint widths vary too much for a single seal profile.
Can I crack-seal in winter?
Cold-weather crack sealing is possible with the right product and preparation, but it is harder and the failure rate is higher. Most D6690 Type I and Type II products have a minimum ambient and substrate temperature on the data sheet — typically 40°F or above. Below that, the pavement is too cold to bond well and cracks tend to be at their widest seasonal opening, which makes them easier to fill but also means the sealant must accommodate large compression as the slab warms up. Spring and fall are the preferred windows in most climates.
What is the difference between a Type I and Type II hot-applied sealant under D6690?
Under ASTM D6690, Type I is the standard-climate hot-applied rubberized asphalt sealant. Type II is formulated for lower-temperature flexibility, meaning it stays elastic at colder service temperatures and is preferred in northern-tier states with long winters. Type III is formulated for higher temperature stability for hotter climates and heavier traffic, and Type IV is jet-fuel and oil resistant for airfield and fueling-area pavements. The differences come from polymer modifications and the published performance criteria in the standard.
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