Up to now three years I’ve visited a good variety of jobsites to see how blacktop crews do a variety of what they do on a day-to-day foundation. Nonetheless, I have never undergone a variety of what I consider as “formal” coaching. Fortunately, final yr I related with Shelly & Sands, a big street work contractor close to the place I dwell in Ohio, and spent a day at their security and coaching facility in Zanesville, OH. There I used to be launched to Void Lowering Asphalt Membranes and educated learn how to safely apply it.
Contractors are nicely conscious that longitudinal joints are sometimes the primary areas of a brand new pavement to fail. Even when the general mat is pristinely laid down, joints can deteriorate early attributable to decrease density on the edges and the intrusion of water and air. Conventional fixes, like notched-wedge joints, echelon paving, or further compaction on the edges, assist however don’t all the time remedy the core difficulty.
Water permeating a poorly sealed joint results in speedy lack of help as underlying layers erode, inflicting cracks and potholes alongside miles of in any other case intact pavement. For this reason companies and contractors have lengthy sought a greater method to shield joints, actually, from the underside up.
What’s VRAM (Void-Lowering Asphalt Membrane)?
It’s basically a thick band of polymer-modified asphalt sealer utilized earlier than paving, on the location of the long run joint, to seal voids and create a moisture barrier inside the asphalt layer. As the recent combine is paved over this strip of fabric, the VRAM softens and “wicks” upward, filling the air voids within the decrease a part of the mat from the underside up. This bottom-up method dramatically reduces permeability on the joint, stopping water infiltration and air intrusion that may in any other case weaken the seam.
Importantly, VRAM is understood by completely different phrases. In most states, the generic specification is VRAM, whereas Illinois refers back to the observe as Longitudinal Joint Sealant (LJS). A number one proprietary VRAM product is J-Band, developed by Asphalt Supplies, Inc. (AMI).
In actual fact, “J-Band and VRAM are equivalent to one another, with one exception: VRAM is bought in a chilly block kind… and J-Band is bought and distributed in a sizzling liquid kind,” defined Invoice Ganger of Cimline, who travels state-to-state offering on-site coaching in software for contractors.
Each varieties create a void-reducing membrane on the joint, however the alternative typically relies on challenge logistics and out there tools.
How VRAM Works to Defend Joints
VRAM cools and solidifies shortly on the pavement floor, so it may be in place hours forward of paving. When the recent prime layer is paved over the handled joint space, the warmth causes the VRAM to soften and wick upward into the brand new asphalt combine, infiltrating about 50–75% of the layer’s thickness.
In impact, the VRAM turns into an integral a part of the joint, filling the voids that remained attributable to barely decrease compaction on the edge. By occupying these void areas, VRAM retains out water and air.
“What we’re doing is filling these void areas up on the sting the place you’ll be able to’t get that full compaction,” mentioned Invoice Ganger, describing how VRAM addresses the pure density drop-off at unconfined edges.
The result’s a dramatically extra water resistant joint. Even when a crack finally varieties on the seam, the penetrated VRAM resin prevents water from permeating downward via the joint because it usually would. The effectiveness of this method can’t be overstated. Attacking the joint downside from inside somewhat than sealing a joint after paving.
Ganger emphasizes that, “We’re fixing that downside from the underside up, as a substitute of making an attempt to place one thing on the highest down… That’s manner higher than making an attempt to pour a sizzling product on prime of a chilly asphalt – it simply doesn’t stream down in as nicely.”
Software: Strategies and Gear
VRAM materials is available in strong blocks just like hot-pour crack sealant blocks. These are melted in an oil-jacketed melter/applicator on website. Cimline’s MA4 is a primary instance of specialised tools for this function.
A typical crew for VRAM software consists of 1 driving the tow automobile alongside the joint line, one working the machine controls, and helpers for loading blocks and high quality management. A machine just like the MA4 can apply on the order of seven,000–10,000 linear toes of VRAM per shift.
The VRAM blocks are melted to an software temperature of roughly 305–340°F, barely decrease than common crack seal materials, which permits the membrane to soften into the overlay extra readily. As soon as sprayed, VRAM cools to a non-tracking state inside minutes, even in average temperatures, that means paving operations and even site visitors can proceed with out sticking or pick-up.
The liquid J-Band materials is delivered as a pre-heated liquid and utilized utilizing a distributor truck, very similar to a tack coat operation. The distributor has a rear spray bar configured to use a slim 18-inch swath of the J-Band on the calibrated software price. This method is commonly used on bigger tasks or DOT jobs the place the paving contractor coordinates for a specialty crew or the provider to spray the J-Band forward of paving.
It has the benefit of excessive manufacturing and integration into regular paving prepare operations. Nonetheless, it requires availability of the liquid materials and applicable truck, which is why many contractors and companies have embraced the melter/applicator route, utilizing tools just like the MA4 affords extra management and adaptability. In both case, the aim is identical: lay a uniform band of VRAM alongside the joint, on the layer under the ultimate carry.
Greatest observe is to use VRAM first, then apply tack coat over the entire floor, together with the VRAM band, simply earlier than paving.
Ganger confirmed that, “The VRAM goes down after which the tack goes on prime of that. The tack is an adhesion promoter, and it doesn’t intrude with the VRAM product in any respect.”
A typical operation for an overlay can be: mill the outdated floor, clear the joint space, spray the VRAM on the uncovered base or intermediate layer, permit a brief cooling interval, apply a light-weight tack coat over every thing, after which pave the brand new overlay.
If a delay is lengthy or there’s site visitors, some crews could mud the VRAM with high quality sand or cement powder to eradicate any slight tackiness, however typically this isn’t wanted because of the quick set time.
Massive Advantages: Longevity and Life Extension
The adoption of VRAM is pushed by its tangible efficiency advantages on the joint. By sealing the joint internally, it slows the standard failure course of. A pavement’s centerline joint that may usually begin cracking and potholing after, say, 5 years might now maintain sturdy for for much longer. The elemental purpose is easy: hold water out.
Even when superficial cracking happens, the crack doesn’t prolong via the total depth of the carry as a result of the voids under are full of asphalt binder. There is no such thing as a water reservoir or trapped air voids on the joint to trigger potholes from under.
Some Illinois DOT’s trials within the early 2000s confirmed that after 14-15 years, sections with LJS had markedly higher joint situation than management sections. More moderen critiques in a number of states have likewise noticed VRAM-treated roads with clear, tight joints years later, versus the raveled and cracked joints of untreated pavements.
The life-cycle price influence is critical. The Illinois DOT estimated a 3-5 yr extension in service life attributable to VRAM, with a benefit-cost ratio as much as 5 occasions the fabric price.
One other profit famous by customers is improved security and look. Since joints stay intact longer, there are fewer work zones wanted for repairs, and vacationers see much less unpleasant crack seal or pothole patches alongside centerlines. Some companies have additionally tied VRAM to their security initiatives, noting that higher joints imply much less water infiltration and fewer hydroplaning dangers or ice formation at seams in chilly areas.
Whereas these secondary advantages are tougher to quantify, they nonetheless help the general worth proposition of VRAM as a part of a top quality ahead paving program.
Rising Adoption Throughout States
States like Ohio, Indiana, Pennsylvania, and Illinois have all adopted VRAM of their paving specs. In actual fact, my state of Ohio has been a pacesetter.
“All the State of Ohio now’s requiring VRAM on each single state bid for any state-paid street challenge,” Ganger famous, that means the Ohio DOT asks contractors to incorporate VRAM of their challenge bids.
This mandate doesn’t assure each challenge will use it, however it reveals the company’s recognition of VRAM’s worth. Ohio’s early expertise, together with tasks by Shelly & Sands, an early-adopter contractor, demonstrated the feasibility and advantages so clearly that Shelly & Sands invested in a number of VRAM applicator machines to fulfill demand.
“That’s why Shelly & Sands received so concerned… they’ve seven machines now, due to this mandate,” mentioned Ganger.
Different states are following go well with. Indiana added VRAM (J-Band) to its state paving specification1 in 2025, recognizing it as a confirmed technique to enhance joint efficiency. Illinois continues to make use of LJS routinely on tasks and has included it in life-cycle profit analyses. Pennsylvania and Illinois have been famous as early adopters alongside Ohio and Indiana, and quite a few different DOTs have trial sections or provisional specs in place.
In line with trade sources8, by 2024 a minimum of 25–27 states had used VRAM on tasks, and that quantity solely continues to develop. Initially most utilization was in colder “snow-belt” states the place freeze-thaw harm made joint failures particularly problematic, however hotter states are actually exploring it as nicely as a result of joint development points are common.
Integrating VRAM into Your Tasks
For contractors, the rise of VRAM represents a possibility to ship higher-quality, longer-lasting pavements. Integrating VRAM is comparatively simple: it entails an additional step within the paving course of, however one that may be well-planned and executed. Coaching is essential although, as crews should be taught the correct software methods and high quality management. Too little materials will probably be ineffective and an excessive amount of might trigger extra bleed.
By way of the place VRAM is finest deployed, any challenge with essential longitudinal joints is a candidate. This usually means multi-lane highways, county roads, and metropolis streets with centerline joints, particularly these anticipated to endure heavy site visitors or harsh climate. VRAM can be helpful for widening tasks or lane additions, the place a joint between new and outdated pavement will probably be current. Some companies have additionally used VRAM on longitudinal joints between sizzling combine and adjoining concrete to forestall water entry.
Whereas primarily utilized in new paving or overlays, the idea might conceivably be utilized in main rehabilitation the place a joint is being reconstructed. The price of VRAM materials and software is a fraction of the general paving job when contemplating the extension in pavement life and discount in future upkeep.
Quite than accepting joints as inevitable weak factors, contractors can ship pavements with strong, sturdy seams that stand the check of time.
