Abstract:
The present invention comprises a method and kit for repairing the wall of a manhole wherein a material capable of curing and hardening is adhered to the wall. An expandable bladder engages the curable and hardenable material and presses against and smoothes the material. The bladder may be chemically bonded.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of pending U.S. patent application Ser. No. 12/959,044, filed on Dec. 2, 2010, which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a method and apparatus for repairing the wall of a manhole. More particularly, but not exclusively, it relates to a method and device for treating the wall of a manhole using a bladder and material capable of curing and hardening, such as a grout or thermoset resin. The bladder expands to conform to the wall of the manhole and the material capable of curing and hardening is disposed between the wall and the bladder or on the interior surface of the bladder. 
     Conventional manholes include a lower or bottom panel, a barrel having a relatively constant diameter adjacent the panel, a concentric or eccentric cone extending upwardly from the barrel, one or more adjusting rings to adjust the overall height of the manhole, and a casting frame on top of the adjusting rings to support an elevation substantially level with the surrounding pavement. The casting frame is preferably sealed to the uppermost adjusting ring to preclude or minimize water flow into the manhole. The cone and adjusting rings are commonly known as the manhole chimney. Most manhole structures are unique in size and shape with varying diameters and depths. Also, bricks often form a portion of the wall of the manhole. 
     Substandard construction methods can lead to damage or deterioration of the manhole structure. Thus the manhole is vulnerable, allowing water and subsidence of soil to enter the manhole, which eventually leads to a structural failure of the manhole. 
     One presently known method of repairing manholes is the placement of a coating of a cementitious grout onto the interior surface of the manhole wall. The grout is applied in an uncured state and is permitted to cure. Methods of applying the grout include troweling the grout onto the wall of the manhole after spraying or slinging the grout onto the wall of the manhole. The manhole wall must be clean and free from water leaking through the manhole walls. Here, it is necessary for a person to enter into the manhole to plug water leaking into the manhole. A final troweling step is usually required by a person entering the manhole in order to obtain the desired compaction, surface and thickness for the curable and/or hardenable material. 
     Additionally, resin, such as an epoxy, a polyurethane, polyuria or other thermo-set resins have been applied to manhole walls by spraying or slinging the polymer onto the manhole wall. The polymer requires the manhole wall to be clean and free from water leaking with a prepared surface adequate for adhering the polymer to the manhole wall. 
     Resin-coated sleeves have also been used for repairing a manhole chimney. However, to accommodate changes in diameter of the manhole, the use of an impermeable coating on the sleeve is problematic, as a substantial coating can prohibit the necessary stretching of the sleeve, because when the sleeve stretches, the coating becomes prone to delamination from the sleeve. Furthermore, applying a coating to a fabric sleeve and sealing the seam of a fabric sleeve increases the cost for producing the sleeve. As such, problems remain in the art and a need exists for an improved method and means for repairing the wall of a manhole. 
     SUMMARY OF THE INVENTION 
     It is therefore a principal object, aspect, feature or advantage of the present invention to provide an apparatus and method for repairing the wall of a manhole which improves over or solves the problems and deficiencies in the art. 
     Other objects, features, aspects, and/or advantages of the present invention relate to an apparatus and method which achieves the desired compaction, surface and thickness for the curable and hardenable material without troweling or otherwise requiring an operator to enter the manhole. 
     Further objects, features, aspects, and/or advantages of the present invention relate to a new method of repairing the wall of a manhole wherein the curable and hardenable material is applied to the wall and an impermeable coating is applied to the outer surface of the material. 
     Further objects, features, aspects, and/or advantages of the present invention relate to a new apparatus and method for repairing the wall of a manhole wherein an impermeable coating is mechanically bonded to the grout or other curable and hardenable material. 
     Still further objects, features, aspects, and/or advantages of the present invention relate to a new method of repairing the interior wall of a manhole wherein an impermeable coating is formed about the manhole wall and adhered thereto with a chemical bond, or in some cases a mechanical and a chemical bond. 
     Still further objects, features, aspects, and/or advantages of the present invention relate to a new method of repairing the interior wall of a manhole wherein a resin impregnated sleeve does not include an impermeable coating maximizing stretching of the sleeve, forming an impermeable coating to the resin impregnated sleeve by adhering an inflatable bladder to the resin impregnated sleeve as the resin cures. 
     A still further object, feature, aspect and/or advantage of the present invention relates to a method and apparatus for repairing the wall of the manhole that accommodates diameter changes along the wall. 
     Further objects, features, aspects, and/or advantages of the present invention relate to a method and apparatus for repairing the wall of a manhole wherein a pressurized, expandable bladder provides a clean dry surface onto which a curable and hardenable material is applied. 
     These and other objects, features, aspects, and/or advantages of the present invention will become apparent with reference to the accompanying specification and claims. 
     One aspect of the invention includes a method for repairing a wall of a manhole that obviates the need for a pre-formed liner. The method generally includes applying a material capable of curing and hardening to the wall of the manhole, positioning a bladder at least partially within the manhole, expanding the bladder under pressure against the wall of the manhole, allowing the material to cure and harden, and removing the bladder from the manhole. 
     In another aspect of the invention, a resin impregnated sleeve may optionally be used and the bladder is left within the manhole after the curing process. A bond is created between the resin and an exterior surface of the bladder after the resin impregnated sleeve is applied to the wall of the manhole and is allowed to cure and harden. In one form, the exterior surface of the bladder is uneven and adapted to be mechanically attached to the cured resin impregnated sleeve. In another form, the bladder is compatible for adhesion with the cured resin impregnated sleeve. Once the material cures and hardens, a mechanical bond and/or a chemical bond are created between the resin impregnated sleeve applied to the wall and the inflation bladder. The bladder is left bonded to the material on the wall of the manhole to create an impermeable coating. 
     Another aspect of the present invention includes a method of repairing a wall of a manhole wherein a bladder is positioned at least partially within the manhole and expanded under pressure against the wall of the manhole. A material capable of curing and hardening is then applied to the interior surface of the manhole and allowed to cure and harden. The bladder provides both an impermeable barrier and a clean dry surface on which to apply the curable and hardenable material. 
     Yet another aspect of the present invention relates to an apparatus for treating a wall of a manhole that includes a material capable of curing and hardening covering the wall of the manhole, a bladder is expanded outwardly with an exterior surface of the bladder being attached to the material on the wall of the manhole and wherein the exterior surface of the bladder creates a mechanical bond, a chemical bond, or both a chemical and mechanical bond with the material on the wall of the manhole. 
     In an alternative form, the apparatus includes a bladder expanded outwardly against the wall of the manhole and the material capable of curing and hardening covers an interior surface of the bladder. 
     The present invention as disclosed herein provides numerous advantages. For example, once a grout or other material capable of curing and hardening is applied to the wall of the manhole, no troweling by hand or similar operation is required to provide for the proper compaction, surface and thickness of the material. A pre-formed liner is not required to practice the invention. In embodiments wherein the bladder is not removed from the wall of the manhole, the bladder effectively becomes an impermeable barrier or coating to the manhole lining. 
     Still further yet, in those embodiments wherein the material capable of curing and hardening is sprayed or otherwise applied to the interior of an expanded bladder within the manhole, the bladder provides a clean surface onto which to adhere the material in addition to an impermeable barrier. 
     Still further yet, the use of an expandable bladder to press a curable and hardenable material against and into cracks and crevices in the wall of the manhole provides for a structurally sound repair not heretofore possible with the prior art spraying and troweling method. 
     These and other benefits and advantages of the invention will become apparent to those skilled in the art based on the following disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a manhole including a sprayer for applying a curable and/or hardenable material onto the manhole walls. 
         FIG. 2  is a sectional view of a manhole where an installation assembly is used in accordance with an embodiment of the present invention. 
         FIG. 3  is a sectional view of the manhole in  FIG. 1 , showing a second view of the preferred embodiment of the present invention. 
         FIG. 4  is a sectional view according to line  4 - 4  of  FIG. 3 . 
         FIG. 5  is a sectional view according to line  5 - 5  of  FIG. 2 . 
         FIG. 6  is a sectional view similar to  FIG. 5  of a modification of the present invention. 
         FIG. 7  is a sectional view similar to  FIG. 5  of a further modification of the present invention. 
         FIG. 8  is a sectional view similar to  FIG. 5  showing a further modification of the present invention. 
         FIG. 9  is a sectional view showing yet a further modification of the present invention. 
         FIG. 10  is a sectional view of the manhole of  FIG. 1  showing another embodiment of the installation assembly of  FIG. 2 . 
         FIG. 11  is a sectional view according to line  11 - 11  of  FIG. 10 . 
         FIG. 12  is a sectional view of a manhole illustrating an alternative embodiment of the present invention. 
         FIG. 13  is a sectional view of a manhole illustrating an alternative embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A typical manhole  10  has a bottom panel  12  that has a run through  13 . The bottom panel  12  is attached to a barrel  14 , a cone section  16 , and a plurality of adjusting rings  18 . A casting frame  20  is mounted at the upper end of the manhole  10 . As can be seen in  FIGS. 1, 2, 3, 10, 12, and 13 , the manhole  10  has a number of diameters D 1 , D 2 , D 3 , and D 4 , as well as irregularities in the wall usually formed of brick, which often become spaced from one another. 
       FIG. 1  shows the initial manhole  10 . A curable and/or hardenable material  42  is sprayed on the wall of the manhole  10  by a sprayer  50 . The material capable of curing and hardening may be a grout, a resin, a thermoset resin, a photocuring resin, or a cementious material. Sprayer  50  has an inside air supply  44  and an outside air supply  46 , which cause sprayer ribs  52  to rotate and throw the curable and/or hardenable material  42  outwardly in the direction of arrow  54 . The sprayer  50  has a feeder  48  which extends downwardly through sprayer  50 . The arrow  56  shows the movement of sprayer  50  in an upward and downward direction. A cementitious grout is preferred, but various construction grouts and resinous materials are suitable for use with the present invention, including resin grouts and thermoset resins such as epoxy resin. 
       FIGS. 2-4  show an embodiment of the invention. Attached to an upper rack  22  is the upper end  24  of an expandable bladder  26  which extends to a lower end  28 . The lower end  28  of the bladder  26  is attached to a lower rack  30 . The lower rack  30  is attached to the upper rack  22  by a post  32  that has a post section  34  telescopically received within a post section  36 , which has a pin  38  securing the post sections  34 ,  36  together. There may be other post sections in addition to post sections  34 ,  36 . A threaded end  40  is within the lower most post section  36  so as to secure the post  32  to the lower rack  30 . Alternatively, the bladder  26  may be attached to the upper rack  22  at the upper end  24  of the bladder  26 , and the lower end  28  of the bladder  26  may be closed by banding or otherwise sealing the lower end  28 . In such an alternative, the lower rack  30  and post  32  need not be used to install the bladder  26  into manhole  10 . 
     The bladder  26  is self-contained and therefore inflatable. The bladder  26  may generally be described as an inflatable, expandable, non-absorbent, fluid impervious film. The bladder  26  is preferably made of thermoplastic polyurethane or another thermoplastic material such as poly vinyl chloride or polypropylene. The bladder material should have a wall thickness of approximately 20-100 mils prior to expansion, which thins to approximately 10-80 mils when expanded against the wall. It is also preferable that the bladder not have a scrim reinforcement, so that the bladder can expand or stretch as necessary to accommodate changes in diameter of the manhole. As such, the bladder  26  may have a single, uniform diameter. With such a bladder, the diameter may be sized to be equal or less than the smallest cross section found within the manhole  10 , which is typically defined by the casting frame  20  and adjusting rings  18 . 
     An air inlet tube  39  extends through the upper rack  22  and is adapted to introduce air to inflate the bladder  26 . The air inlet tube  39  or a separate inlet may be used to introduce steam or another heated fluid when thermoset resins are used. Alternatively, a UV light may be integrated into the upper rack  22  so as to extend into the bladder  26 . 
       FIG. 5  shows the bladder  26  with an exterior surface  60  in contact with a curable and/or hardenable material  42 . As shown in  FIG. 5 , there are no projections extending from the bladder  26  into the curable and/or hardenable material  42 , and consequently there is no mechanical bond. However a chemical bond exists between the bladder  26  and the curable and/or hardenable material  42  upon the curing and hardening of the material, forming an impermeable coating or barrier that becomes an integral part of the manhole. In order to exploit this feature of the invention, it is preferred to use a bladder material that is compatible for adhesion with the curable and hardenable material. A preferred combination to create a chemical bond is the use of an epoxy as the curable and hardenable material and the use of thermoplastic polyurethane as the bladder material. However, other combinations are within the scope of this invention. The bladder  26  as illustrated in  FIGS. 6-9  is intended for use in applications where the bladder  26  remains fixed to the curable and/or hardenable material  42  after it cures and hardens, thus becoming an impermeable coating or barrier by a mechanical bond. Here, the exterior surface  60  is uneven and preferably includes a plurality of projections or protrusions. Referring to  FIG. 6 , a surface  60  of the bladder  26  includes straight pointed projections  62  extending in opposite directions and embedded in curable and/or hardenable material  42 .  FIG. 7  shows a plurality of curved pointed projections  64 , and  FIG. 8  illustrates T-shaped projections  66 . All of these projections  62 ,  64  and  66  provide a mechanical bond between the bladder  26  and the curable and/or hardenable material  42 , as the projections become embedded and trapped within the curable and/or hardenable material  42  once the curable and/or hardenable material cures and hardens. Projections having other shapes can be used to create a mechanical bond between the bladder  26  and curable and/or hardenable material  42 . 
     The projections depicted in  FIGS. 6-8  may be formed when the bladder material is made by an extrusion process. In such a process, raw material for forming the bladder is extruded through a series of rollers and allowed to set. At least one of the rollers may be embossed with a texture to impart the projections onto the material. 
       FIG. 9  illustrates an alternative embodiment of the bladder  26  that is intended for use in applications where the bladder  26  remains fixed to the curable and/or hardenable material  42  after it cures and hardens, thus becoming an impermeable coating or barrier via a mechanical bond. In this embodiment, the mechanical bond is formed by the use of pores  67  within the bladder  26 . The pores  67  may be formed within the bladder material by an extrusion process or like as described above, or the pores  67  may be formed by stretching or abrading the material of the bladder  26 . The stretching may be performed by inflation and expansion of the bladder  26  after placement within the manhole. In operation, the pores  67  are formed within the material of the bladder  26 . The bladder  26  is expanded against a manhole wall. As the material of the bladder  26  stretches, the pores  67  open to accommodate the flow of curable and hardenable material within the pores  67 . The curable and hardenable material cures within the pores  67  and anchors the material of the bladder  26  to the wall of the manhole. 
     The method of repair illustrated in  FIGS. 1-4  is as follows. First, the manhole  10  is sprayed by sprayer  50 , such as shown in  FIG. 1 . The sprayer  50  is passed upwardly and downwardly as shown by arrow  56  until the surface area of the wall  43  is covered. The thickness may vary depending upon the condition of the manhole  10 . 
     The installation assembly, comprising the upper rack  22 , the optional lower rack  30 , and the bladder  26 , is inserted into the manhole  10  with the post  32  threaded into the lower rack  30 . Initially the bladder  26  hangs loose within the manhole  10  and is not in contact with the curable and/or hardenable material  42 . The bladder  26  is then inflated by introduction of a fluid into the fluid intake  39 . Because the bladder  26  is expandable, it moves into contact with the curable and/or hardenable material  42  as shown in  FIG. 2 . The fluid can be hydraulic fluid, water, or air, and could be other fluids as well. 
     The bladder  26  presses against the curable and/or hardenable material  42  so as to smooth it and also to cause the curable and/or hardenable material  42  to press against the number of diameters D 1 , D 2 , D 3 , and D 4  (as well as other diameters) and to penetrate cracks and crevices in the wall of the manhole  10 . This is superior to troweling, which cannot achieve the same penetration of the curable and/or hardenable material  42 . Troweling also requires the operator to enter the manhole  10 . With the present method of operation, it is not necessary for an operator to enter the manhole  10 . 
     The curable and/or hardenable material is then cured and hardened within the manhole  10 . The curable and/or hardenable material may be cured by the accepted method known for curing the material. For example, the curable and/or hardenable material may be cured by the use of introducing steam within the bladder  26  for a thermoset resin or the introduction of a UV light or the like for a photocuring resin. Once the curable and/or hardenable material  42  has cured and hardened, the bladder  26  may be entirely removed from the manhole  10  or the portion contacting the curable and/or hardenable material  42  may be left in place. In applications where the bladder  26  is removed, it is preferable to use a non-stick bladder material as disclosed in U.S. Patent Publication No. 2009/0194183, which is incorporated herein by reference in its entirety. In such an embodiment, no projections or protrusions should be disposed on the exterior surface of the bladder  26  to ensure the bladder  26  does not stick to the curable and/or hardenable material  42 . Using this particular repair or treatment method, the curable and/or hardenable material is smoothed and penetrates cracks and crevices in the wall of the manhole  10 . However, it is preferred to leave the bladder  26  within the manhole  10  to use it as an impermeable coating or barrier. Here, the bladder  26  is cut adjacent the upper end  24  and the post is unthreaded from its attachment to lower rack  30 . The installation assembly, including the upper and lower rack  22 ,  30  and the post  32 , is removed from the manhole  10  to form the manhole lining. 
     This leaves the manhole  10  as shown in  FIG. 3 . A handle  96  with a knife  98  is inserted and the knife  98  cuts the bottom of the bladder  26  into a circular cutout  99 . The excess bladder material is removed from the bottom of the manhole  10 , and the resulting manhole  26  is shown in  FIG. 4 . The handle  96  may or may not be utilized, as it allows an operator to stand outside of the manhole while cutting and removing excess material. Alternatively, the operator can enter the manhole  10  to cut and remove excess material. Alternatively, a saw, grinding tool, sander, or other cutting tool may be used to remove or smooth excess or unneeded portions of the bladder and cured material. It should also be noted that the  FIGS. 3-4  illustrate where the bottom of the bladder is cut out around the periphery of the floor of the manhole  10 . However, the lining of the entire manhole floor need not be removed. As such, the knife  98  or other cutting tool may simply be used to remove the lower rack  30  and to reinstate access to the run through  13 . Similarly, the knife  98  or other cutting tool may be used to remove excess bladder and other material extending above the casting frame  20  of the manhole  10  after installation of the manhole lining. 
     As an alternative to positioning the stretchable material or bladder  26  in the manhole and then expanding it radially outwardly toward the manhole wall, it may also be inverted into the manhole. This is illustrated in  FIG. 10  wherein an inverter  72  is self-contained within an above ground inverter  74 , and a bladder  82  is within the above ground inverter  74  and is reversed with its outside presented inwardly and its inside presented outwardly. 
     A plug  76  is inserted within and attached to the above ground inverter  74 . The plug  76  contains a fluid introducer  78  and a pull rope  90  having a lower end  92  and an upper end  94 . The upper end  94  extends through a hole in the plug  76 . Fluid introducer  78  may be used to introduce steam or another heated fluid where thermoset resins are used. In such an application, the use of a heated fluid will permit or encourage curing and/or hardening of the thermoset resin. Alternatively, a separate inlet or port may be integrated into the plug  76  to accommodate the use of a heated fluid. 
     A rigid ring  80  is placed within the casting frame  20  and an upper end  84  of the bladder  82  is attached to the rigid ring  80 . A lower end  86  of the bladder  82  is attached to a pull device  88 . The lower end  92  of the pull rope  90  is attached to the pull device  88  for embodiments where the bladder  82  is removed from the manhole  10 . The pull rope  90  may also be utilized for embodiments where the bladder  82  is left within the manhole  10 . In such applications, the pull rope  90  may be marked at the upper end  94  prior to the inversion process so that a technician may be able to determine when the bladder  26  is fully inverted into the manhole. 
     The bladder  82  is reversed or inverted into the manhole  10  with its inside presented outwardly and its outside presented inwardly. The inversion can be caused by a fluid (either gas, air, or hydraulics) that is introduced by the fluid introduction device  78 . The bladder  82  expands into contact with the curable and/or hardenable material  42 . If a photocuring resin is used with a UV light or the like, then the bladder  82  should be made from a translucent or semi-transparent material (as known in the art). This allows a UV light to be lowered into the manhole for curing. 
     The bottom portion of the bladder  82  can be cut out (as previously described) and removed from the manhole  10  by pulling on the end  94  of rope  90 . The remaining portion of the bladder  82  is left within the manhole  10 . The same modifications as shown in  FIGS. 5-8  can be applied to the bladder  82  and the curable and/or hardenable material  42  to create a chemical bond  61  or a mechanical bond or both. Again, the inflatable bladder  82  or other stretchable material acts as a coating on the curable and/or hardenable material  42 . 
     A second embodiment is illustrated in  FIG. 12 . In this embodiment, a manhole liner  100  is used as an alternative to the sprayer  50  and the bladder  82  is left in the manhole  10  to create an impermeable barrier on the walls of the manhole  10 . The manhole liner  100  is generally a fabric capable of being impregnated with a curable and hardenable material. The manhole liner  100  may be a stretchable sleeve that can be used to repair and renew manholes having various sizes. In one embodiment, the manhole liner  100  is a one-size fabric liner which stretches circumferentially to various diameters up to 150% of the unstretched diameter for use in manholes of varying sizes and shapes. U.S. Pat. No. 7,670,086 and U.S. Pat. App. No. 2010/0018631 describe such liners and are incorporated by reference in their entireties. 
     Where the bladder  82  is to be left within the manhole  10  by the use of a chemical bond, the bladder  82  is preferably constructed of a polyurethane and the curable and hardenable material is preferably an epoxy. However, other combinations of bladder material and material capable of curing and hardening are considered for use as long as they are compatible and conducive for adhesion. Where the use of a mechanical bond is desired, the material of the bladder  82  should include the projections or pores as described above. 
     In operation of the second embodiment, the manhole liner  100  is impregnated with a material capable of curing and hardening. The manhole liner  100  is then placed into the manhole  10  by attaching an upper portion  70  of the manhole liner  100  to a flange member  68  above the manhole  10 , adjacent the casting frame  20 . The manhole liner  100  is then inserted into the manhole  10  and placed against the walls of the manhole  10  by a bladder  82  that is used to expand the manhole liner  100  against the walls of the manhole. In the embodiment depicted in  FIG. 12 , the bladder  82  is inverted into the manhole  10  by attaching the bladder  82  to an above ground inverter  74 , inserting the plug  76 , and providing a fluid to the bladder  82  using fluid introducer  78 . The pull rope  90  may be used to measure the depth of the bladder  82  as described above. The material capable of curing and hardening is allowed to cure and harden, providing a lining to the manhole  10  where the manhole liner  100 , the cured and hardened material, and the bladder  82  become an integral part of the manhole  10 . In embodiments where a chemical bond between the bladder  82  and the curable and/or hardenable material is desired, steam or heat may be introduced into the manhole  10  during the curing process to promote integration of the bladder  82  to the material capable of curing and/or hardening. Once the material is fully cured and/or hardened, areas of the lining that are unnecessary are cut away and removed from the manhole  10 . 
     It should be noted that  FIG. 12  shows where the bladder  82  is placed into the manhole  10  by the use of an inversion process for the bladder  82  after the manhole liner  100  is attached to the casting frame  20  of the manhole  10  by the use of a flange member  68 . However, an inversion process is not required to practice this embodiment of the invention. Alternatively, the installation assembly as described in reference to  FIG. 2  may be used to press the manhole liner  100  against the manhole walls. It should also be noted that all methods of the present invention should not be limited to the order of the recited steps. For instance, the manhole liner  100  may be impregnated with the material capable of curing and hardening before being placed into the manhole  10 . Alternatively, the material capable of curing and hardening may be placed onto the manhole walls, and the manhole liner  100  may be impregnated by the material capable of curing and hardening after insertion into the manhole  10 . 
     An alternative embodiment is illustrated in  FIG. 13 . Here, the bladder  26  is inflated and expanded against the wall of the manhole  10  prior to applying a curable and/or hardenable material  42 . The curable and/or hardenable material  42  is applied to the interior surface  63  of the bladder  26  while the bladder is maintained under pressure and conforms to the wall of the manhole  10 . The curable and/or hardenable material  42  is then allowed to cure and harden, and portions of the bladder  26  are cut out and removed as previously described. In the illustrated embodiment, the sprayer is adapted to be an integral part of the installation assembly and the spray ribs  52  are movable along the post  36  between the lower rack  30  and the upper rack  22 . 
     This alternative embodiment has several advantages. The bladder  26 , preferably made of TPU with a wall thickness of 20-100 mils prior to expansion, provides a clean dry surface on which the curable and/or hardenable material is applied. The bladder also provides an impermeable barrier against the wall of the manhole that prevents ground water from washing away the curable and/or hardenable material and entering the manhole. 
     The invention has been shown and described above with the several embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.