Case Study 1 - Corrosion Inhibition

Project: Isaac's Parking Garage - Milwaukee, WI

Date Performed: July, 2000

The Problem
The cast-in-place eight level parking structure, approximately 28 years old, was suffering from water and deicing salt infiltration causing a number of corrosion related problems throughout the structure. The moisture and chlorides had migrated down to the reinforcing steel causing the concrete cover to delaminate, crack and spall. In many areas, cracks had allowed a direct pathway for water and chlorides (salts) to reach the reinforcing steel leading to accelerated corrosion in those areas (hot spots).

While most of the deterioration in the structure was clearly visible, underlying corrosion not yet seen (latent corrosion) was also a cause of concern for future deterioration.

As in most Surtreat projects, a variety of diagnostic tests were performed to evaluate the existing condition of the garage and gather data to implement the site-specific solutions phase of our system. Our analysis confirmed that corrosion was active throughout the garage. Testing also showed a carbonation problem in various areas.

Surtreat Solution
To achieve the desired results (a decrease in electrochemical activity - corrosion, increase in compressive strength and increased pH levels), two formulations were chosen and applied via low-pressure spray units and scrubber machines to all columns, beams, walls, floors and the underside of all eight levels of the garage.

Results
The Surtreat formulations used migrated in excess of 2" below the surface re-establishing the passivating film on the reinforcing steel - halting corrosion. Increased compressive strength, reduced porosity, bridging of micro-cracks and an elevation in pH were also achieved. Over 280,000ft² of area was treated.

Case Study 2 - Chemical Attack

Project: Johnson Control Battery Charging and Storage Facility - Fort Wayne, IN

Date Performed: June, 1999

The Problem
The steel trowel finished concrete floor of the facility (approximately 146,000ft²), began showing early signs of concrete deterioration such as pitting, spalling, impact and abrasion damage along with chemical deterioration. Concerns of accelerated concrete deterioration due to sulfuric acid attack from the facility's manufacturing process were of major concern for the facility managers on site.

Surtreat Solution
Upon the completion of pre-testing, and minor spall repairs, a combination of Surtreat's formulations were selected, manufactured and installed over the entire surface of the 146,000ft² floor. The Surtreat formulations were applied via low-pressure spray equipment and scrubbing machines. The formulations used were designed to penetrate into the gel pores of the concrete to two different depths and react with the cement phase to modify the chemical and physical properties.

Results
The post-application test results verified an increase in the floor's compressive strength, a reduction in porosity and most importantly a significant reduction in its chemical reactivity.

Case Study 3 - Strengthening

Project: Allright Parking, Inc. - Columbus, OH

Date Performed: September, 1989

The Problem
This 10 level parking structure was constructed 35 years ago. Eight of the ten levels are above ground and had experienced severe spalling and delamination caused by water and deicing salt penetration that had reached the steel reinforcing bars thereby activating corrosion. The deleterious effects of corrosion were such that nearly on a weekly basis it was necessary to remove loose and friable concrete from portions of the structure’s ceiling to avoid falling debris and potentially serious accidents. For a period of 5 years prior to Surtreat’s initial analysis, the facility was annually inspected by a Columbus, Ohio engineering firm requiring the garage to conventional “cut and patch” repair programs. The Vice President of Allright Parking, Inc. said it was necessary to allocate at least $20,000 per year for these repairs. The cut and patch repair program did not improve the continuing deterioration that was taking place. In June of 1989 the City of Columbus Building Engineer advised the owner that the facility would be condemned and closed by the City unless substantial repairs were made immediately. Numerous proposals submitted by other firms to Allright Parking, Inc. to perform the necessary repairs exceeded an estimated cost of $2,000,000.

Surtreat Solution
Surtreat offered a significantly less expensive approach for restoring the original properties of and protecting the garage from further deterioration. The history of the structure was reviewed by Surtreat personnel to provide the customer a long-term solution to the corrosion problem. Preliminary testing results confirmed that chloride content levels in the concrete were extremely high and that the concrete was also fairly weak and porous. Utilizing a proprietary chemical system developed at its Pittsburgh, PA based laboratory facility, Surtreat proposed treating the symptoms throughout the facility by using its newly developed system of chemically reactive formulations that react with Portland cement and reinforcing steel to inhibit further corrosion, seal the pores, micro cracks and to increase surface hardness, compressive and flexural strength. Uneven floor surfaces were patched with a Surtreat proprietary cementitious coating utilizing high performance polymer modified Portland cement. During the application process it was necessary to adjust the formulations and application procedure due to fluctuations in the cement matrix from floor to floor. The higher levels required significantly more attention than the lower levels as a result of excessive water that must have been used to transport the cement mix to the higher levels. The water based, inorganic formulations were applied using low-pressure spray application.

Results
Surtreat’s turnkey approach was an attractive alternative to the somewhat antiquated and significantly more expensive methods proposed by the various engineering-consulting firms. Our full service system was successfully executed resulting in a cost savings of nearly 90%, saving Allright Parking, Inc. more than $1.8M.

During the most recent survey of the parking structure in 2002, the system is still performing optimally. Since the treatment, nearly 13 years later, the facility no longer has the rampant deteriorative process that was evident in 1989. The facility is fully utilized to date.