Bridge decks are notoriously difficult and expensive to maintain because of water penetration complicated by de-icing treatments (especially salt) and wide temperature fluctuations. Inspection of bridge deck surfaces usually reveals wheel ruts, asphalt fragments and concrete damage.

MacPave has been used to provide a barrier between the concrete and the blacktop to minimize the differential between the temperature response of the two materials. Additionally, heavy traffic, such as loaded trucks, will cause a bow wave, analogous to that produced by a ship moving in water, on the surface of even a rigid concrete bridge - again, adversely affecting the surface quality of the deck.

MacPave can aid substantially in bridge deck surface maintenance. Initially, the deck must be cleaned down to the concrete when it should be inspected for damage from salt treatments. The concrete is then sealed to prevent further salt penetration, after which the membrane can be installed without the usual bitumen, but using a special joint seal - MAC120 - which provides a 100% water seal and glues the membrane to the concrete, at the same time allowing gases in the concrete to escape.

A base asphalt is then laid on top of the membrane according to local specifications. This in turn is covered with a draining asphalt with open stones to minimize slippery conditions if icing occurs.

Comparable procedures with MacPave can be successfully applied when watersealing underground tunnels and pedestrian subways and many other applications.

From many years experience as a compacting and applying engineer at asphalt and roller company's, I have been traveling around the globe to learn about and train customers and employees re spraying asphalt liquid, tack coats and compact asphalt. And I have found that bridge decks are the most complicated thing to do.

Normally there is a very compact traffic situation with lots of load pressure on a compact area. That means wheel ruts, showed asphalt and "ski jumps" in the expansion joints. When this happens, you are getting damage even to the structure, both on concrete and steel constructions near the joints - mostly in concrete decks.

An asphalt overlay behaves like water. When a heavily loaded truck is driving over the bridge, the wheels are pressing the asphalt overlay like a bow wave to the steel joint and making a "ski jump." And when this happens, even a small car starts to jump, and very soon that creates a micro vibration at low amplitude which spoils the concrete and reinforcement bars. (The moisture has a chance to penetrate the concrete from underneath and sides and starts to rust the metal bars. This creates a very inconvenient situation, both for the drivers and the owners of the bridges.

It's always complicated to repair a bridge as there are not many alternatives for routing the traffic, rush hours and others things. But with our MacPave membrane, you are reducing the problems with your bridge decks and prolonging the life by several years. (See the two steel joint graphics above and below.) It also makes your bridge safer for drivers if there are no bumps on the joints.

Believe it or not, we were surprised when we became involved with waterproofing railway bridge decks and discovered a side effect was the soundproofing. We were reducing the sound in the structure down by 10-15%. Sometimes life is full of surprises! We are using a special, heavy type of asphalt in our mastic, and together with our patented mixing, it becomes very heavy. (A theory is that materials which best perform the function of vibration damping are in the form of a heavy, high-density mass. Further movement of structural material is communicated to the damped material with the dissipate effects of the flexure and internal friction inherent to the deadener.)


Many have tried to copy our philosophy, but so far we are number 1 to avoid reflective cracking to return on your overlays. When you are waterproofing your bridge decks with MacPave, you get the second effect that there are no microwaves from the traffic spooling your bridge structure with costly repairs. And most importantly, our membrane with the polyester reinforcement is strong enough to withstand the movement in the overlay to avoid breaking the waterproofing capability in the membrane. That means you can use larger stones in the overlay and a smaller amount of filler to get a stronger overlay to reduce the wheel ruts. You can also use a more open asphalt to reduce the ice problems in cold areas in the top layer.

The textile in our membranes is not affected by the acids or chlorides from de-icing operations. MacPave saves a lot of money and inconvenience for you and the users of the bridges.

Bridge isolation in Ohio: This was a test with only a handyman's way to do it. Notice the MAC 140 was used to glue the membrane to the bridge deck and then roll it out. Notice also the overlapping edges have to be at least 2-3 inches (6-9 cm) after sealing the edges. This is very important with the material MAC 140 and also with rubberized material.

Water penetration leads to quicker bridge deck deterioration, especially when subjected to freeze-thaw cycles. MacPave reduces moisture interpenetration between new and old pavement surfaces, thereby adding durability to the resurfaced pavement.

In addition to waterproofing, MacPave's heavy-duty, yet flexible construction retards reflective cracking on bridge decks. MacPave retards the reflective cracking of bridge deck overlays usually associated with cracks and joints in the underlying pavement, particularly in cases when flexure and thermal movement of underlying bridge slabs and/or seams occur.

Repairs last longer when stress concentrations are relieved. MacPave's specialized asphalt compound has the right combination of density and thickness to spread wheel loads over repaired areas and retains nearly all of its original thickness for years of protective service.