1-Damaged Pier Cap.jpg

Morganza Spillway

The Problem

  • Proper perseveration of repair mortar applied to structural concrete is needed to extend the life of the repair, which will extend life of concrete structures.

  • It is well known that the best way to protect repair mortars and structural concrete is to prevent water ingress that causes carbonation and allows for organic growth and biological acids, leading to subsequent deterioration.

  • Liquid ingress should be reduced considerably with a coating. In addition, the coating should allow vapor pressure release for it to be durable. 

The Zirconia Solution

Use a thin penetrating inorganic polymer coating CeramycShield™ to:

  • Prevent the ingress of water, while also allowing vapor pressure release.

  • Create a durable coating that is chemically compatible with repair mortars and concrete.

  • Create a high pH stable coating that is inhospitable for organic growth.

 The cementing part of CeramycShield™ is characterized as an inorganic polymer or a “geopolymer.” It was originally developed as a bulk mortar and subsequently modified for use as a coating material for concrete and cementitious surfaces. The cementing part is a potassium alumina-silicate, or polysialate-silox with the general chemical structure:

Kn{ - ( SiO2 z - AlO2 )n } ·wH2O

The resin hardens to an amorphous (glassy) structure at moderate temperatures of 55 to 85°F. Hardeners have been developed to obtain a room temperature cure in 24 hours or less. The unique features of the matrix are as follows:

CeramycShield™ is prepared by mixing the liquefier component with ceramic powder component and then adding the densifier component. The components are mixed to a thin paint like consistency. Since the matrix is water based, tools and spills can be cleaned with water. All of the components are non-toxic, and no fumes are emitted during mixing or curing. Common application procedures such as brushing and spraying can be used for the application. The excess material or material removed from the old application can be discarded as general waste.

Demonstration Project

CeramycShield™ was used for a demonstration project with the Louisiana Department of Transportation and Development (DOTD) on the Morganza Spillway Bridge structural repair and rehabilitation of the Pier Cap.

The major steps of application procedure were:

  • Damaged structural concrete surface, shown in Figures 1 and 2, was cleaned by pressure washing to remove loose concrete and moss growth.

  • Repair mortar was applied to structural concrete Pier Cap, shown in Figure 3.

  • CeramycShield™ was applied to existing structural concrete and repair mortar on Pier Cap, shown in Figures 4 and 5.

  • Surface was evaluated and photographed after 5 Years, shown in Figures 6 and 7.

Performance Over 5 Years

 CeramycShield™ was monitored for 5 years to assess the long-term performance.

  • CeramycShield™ is performing well and looks similar the day it was coated.

  • No structural concrete deterioration is observed, and the repair mortar has remained well protected.

  • Moss growth continues to occur on uncoated concrete but has not occurred on CeramycShield™, shown in Figure 8.

  • Extreme weather conditions, including Hurricane Isaac, did not affect performance of CeramycShield™.

Conclusion

The surface of the Pier Cap was treated successfully with CeramycShield™ in real world field conditions and has shown excellent performance for 5 Years.  There are no signs of spalling, cracking, or other deterioration for either the repair mortar or structural concrete from carbonation, moss growth, or extreme weather.

Figure 1: Damaged Pier Cap

Figure 2: Damaged Pier Cap (note organic growth and vertical penetrating cracks)

Figure 2: Damaged Pier Cap (note organic growth and vertical penetrating cracks)

Figure 3: Repair mortar applied to Pier Cap

Figure 3: Repair mortar applied to Pier Cap

Figure 4: CeramycShield™ applied over repair mortar and structural concrete of Pier Cap (photo taken just after application)

Figure 4: CeramycShield™ applied over repair mortar and structural concrete of Pier Cap (photo taken just after application)

Figure 5: CeramycShield™ applied over repair mortar and structural concrete of Pier Cap (photo taken 24 hours after application)

Figure 5: CeramycShield™ applied over repair mortar and structural concrete of Pier Cap (photo taken 24 hours after application)

Figure 6: CeramycShield™ on Pier Cap after 5 Years

Figure 6: CeramycShield™ on Pier Cap after 5 Years

Figure 7: Close up view CeramycShield™ after 5 Years

Figure 7: Close up view CeramycShield™ after 5 Years

Figure 8: Uncoated surface (left) shows biological staining, while CeramycShield™ (right) remains clean

Figure 8: Uncoated surface (left) shows biological staining, while CeramycShield™ (right) remains clean