1. Field of the Invention
The present invention relates generally to systems and methods for sealing joints in large structures such as roadways. More particularly, the present invention is directed to providing seals in roadway joints that are resistant to water penetration over relatively long periods of time.
2. Description of Related Art
Roadways come in many different sizes and shapes. Roadways may be located directly on land or they can take the form of bridges that extend over water or other non-aqueous features. Roadways are typically made from a wide variety of materials including asphalt, concrete and metal. In many situations it is necessary to form a lateral gap or joint in the roadway to allow for independent movement of the adjacent roadway sections. Such movement is caused by many factors including expansion and contraction of the adjacent roadway sections due to changes in temperature. Roadway gaps or joints are especially critical in elevated structures such as bridges and parking garages. Relative movement of the roadway sections tends to be greater for elevated structures than for roadways located on land. In addition, temperature induced expansion and contraction is more of a problem for elevated structures because temperature fluctuations tend to be more rapid and of a greater magnitude than for roadways located on land.
A multitude of seal systems and configurations have been used to seal roadway joints. Seal systems vary depending upon the roadway type and the size of the joint being sealed. One popular technique involves pressing a flexible rod or tube into the joint. The remainder of the joint above the tube is then filled in with a sealant of some type. The rods or tubes are typically made from some type of foam material and are commonly referred to as xe2x80x9cbacker rodsxe2x80x9d. Other types of seal systems utilize flexible gaskets and combinations of gaskets with sealants and structural reinforcements to provide sealing of the roadway joint. Examples of a variety of sealing systems that have been proposed for sealing joints in roadways are set forth in the following U.S. Pat. Nos.: 3,951,562; 4,245,925; 4,305,680; 4,367,976; 4,374,442; 4,447,172; 4,824,283; 4,927,291; 5,007,765; 5,026,609; 5,071,282; 5,168,683; 5,190,395; 5,607,253; 5,649,784; 5,664,906; 5,935,695; and 6,039,503.
The goal of any roadway joint seal system is to prevent water and other contaminants from entering the joint and to provide a durable surface over which vehicular traffic can pass. It is important that the seal be effective over relatively long periods of time and that it function properly even when exposed to extreme weather conditions. A major problem with many roadway joint seals is that they start to leak after relatively short periods of time. This is a particular problem in high moisture environments where the seal is exposed to water on a continual basis. Water entering the joint can cause relatively rapid deterioration of the roadway surrounding the joint. This is especially a problem in steel reinforced roadways where corrosion of the steel reinforcing material can seriously weaken the joint.
There presently are many types of seal systems that provide adequate sealing of roadway joints. Even so, there still is a continuing need to provide new sealing systems that are effective in protecting roadway joints over relatively long periods of time. Such sealing systems should be suitable for use in sealing new roadway joints. They also should be suitable for use in replacing existing seals in roadway joints that have deteriorated or otherwise failed.
In accordance with the present invention, systems and methods are provided for sealing roadway joints. The term xe2x80x9croadway jointsxe2x80x9d as used herein is intended to encompass all types of joints present in any structure that is intended to accommodate vehicular traffic. Roadway joints include all types of joints, including expansion joints that are present in concrete and asphalt highways located directly on land as well as elevated structures, such as bridges, parking garages, highway overpasses and the like.
The sealing system in accordance with the present invention is designed to seal joints in the roadway wherein the joint has a first wall and a second wall that define a space between the walls. The system includes a first nose plate that is attached to the first wall of the joint to be sealed. A second nose plate is attached to the second wall of the joint. Once attached, the first and second nose plates define a gap between the two interior walls of the nose plates. A lower seal element is located in the gap between the interior walls of the nose plates. A vapor barrier is provided that extends between the top portions of the two nose plates. The vapor barrier includes a first edge portion that is attached to the top of the first nose plate, and a second edge portion that is attached to the top of the second nose plate. Two anchor caps are provided which are used to anchor the edge portions of the vapor barrier to the tops of the nose plates. The combination of vapor barrier and anchoring caps provides a water-tight seal which is especially effective in preventing moisture from entering the joint over relatively long periods of time.
The sealing system in accordance with the present invention as described above may further include an upper seal that is located above the lower seal element and extends between the top portions of the two nose plates. Depending upon the size of the gap between the two nose plates, the upper seal may be formed from a curable liquid sealant or a preformed gasket.
The present invention also includes methods for sealing joints in roadways. The methods involve attaching nose plates to opposing sides of the joint such that the interior walls of the installed nose plates define a gap between the two plates. A lower seal element is then installed in the gap between the two nose plates. The vapor barrier is then installed and anchored to the top of the nose plates utilizing anchoring caps that are designed to clamp the vapor barrier to the nose plates. The method may further include the step of installing an upper seal located above the lower seal element wherein the upper seal extends between the top portions of the nose plates. Again, depending upon the size of the gap, the upper seal may be formed by applying a sufficient amount of a sealant to the gap to provide a sealant body that extends between the anchor caps located on the nose plates or the upper seal can be a preformed gasket that is installed into the gap and anchored to the nose plates using the anchor caps.
The above described system and method for sealing roadway joints may be used in new construction or to replace existing seals that have deteriorated or otherwise failed. The present invention is especially useful in sealing joints in elevated roadways such as bridges, parking garages and overpasses. The system is useful in high moisture environments, such as the tropics, where it is important to maintain a watertight seal.