Turnpike Bridge EB-526
Problem
Turnpike was looking for solutions for bridge deterioration and increasing structure life back in the mid-90s. A SURTREAT® demonstration was conducted on Turnpike Bridge EB-526 over Sandy Hill Road at mile post 279.31. Some signs of rebar corrosion and deterioration were present. The bridge deck was an asphalt surface over reinforced concrete.
Solution
SURTREAT® products were spec’d and used to protect all concrete surfaces and to extend the life of the structure significantly.
SURTREAT® is a proprietary, water based, environmentally friendly solution of activators and migratory aids that inhibits rebar corrosion, increases strength and reduces porosity in reinforced concrete.
SURTREAT® Solutions
- Inhibits salt, water, air and contaminates from penetrating the concrete and forms a better seal in the pores and micro cracks
- Controls pH and maintains the high alkalinity in the concrete and is highly acid resistant
- Migrates to the rebar in liquid and ionic phase and reacts to form a very stable passivating film – more stable than in new concrete
- Converts rust to a stable, inert compound – and increases compressive, flexural, and tensile strength. Also increases hardness and abrasion resistance
Turnpike Bridge EB-526
Cleaning and Rinsing Turnpike Bridge
Asphalt Applied to Bridge Deck
Sealed Deck Curb Interface
Felt to protect Permaquick.
Permaquick Application
Milled Bridge Deck Surface
Hot Rubber Application
The joints at the roadway/deck interface were sealed with hot rubber and reinforced. The deck/curb interface was sealed by bonding rubber sheet onto the surface.
Concrete Solution Applied to Center of Bridge
Water repelled – not soaking in.
Concrete Solution Applied to Surface
Scope of Work
- The asphalt deck overlay was removed and the deck surface milled. The 12,000 SF of concrete surfaces cleaned using cleaning solution applied with a pressure roller and a pressure wash rinse.
- Two applications of SURTREAT® customized concrete solutions were applied with a pressure roller to all concrete surfaces and allowed to penetrate and cure for a day.
- Applied SURTREAT® liquid solution to the concrete to decrease water permeation by up to 97% and extend life by approximately 20 years – was applied to the treated surfaces.
- All cracks in the concrete surfaces were filled with a moisture curing urethane elastomer.
- Two days of SURTREAT® curing on the deck. Asphalt tack coat was then applied, followed by Permaquick – a hot liquid rubber membrane poured in place to 100 mm thickness.
- The Joints at the roadway/deck interface were sealed with hot rubber and reinforced.
- The deck/curb interface was sealed by bonding rubber sheet onto the surface.
Project Results & Measurements
- The cleaning process improved bridge appearance, removed salt and acid residue, as well as mold. Those factors lead to concrete deterioration and opens the micro pores to receive the Surtreat®.
A. Concrete Strength
The concrete strength was measured using the CAPO Pull Out Method, which measures the force needed to pull a 2” dia. x 1” long plug from the concrete. This force is measured in KN and converts as follows:
|
Condition |
Pull Out Force (KN) |
Equivalent Compressive Strength (psi) |
|
Before Application |
22.3 |
3215 |
|
After Application |
32.8 |
5038 |
|
Increase |
10.5 |
1823* |
*This increase may be unexpectedly high. The “Before” plug shattered on pullout while the “After” plug came out in one piece. However, strength increases of 2400 and 980 psi were documented on 2 PennDot bridge projects done around the same time. The “Amount of Increase” is largely a function of the age and condition of the concrete in the test specimen. Weaker, more porous concrete shows greater increases.
B. Water Permeability
Water Permeability was measured on the bridge deck curb using a Germann Instrument Pressurized Water Permeability Cell. The cell is clamped on the curb surface and has a glued gasket. The cell is filled with water and pressurized to one Atmosphere (14.7 psi) and the rate of water penetration was measured in cc/minute.
| Condition | Specific Measurement | Rate in cc/min |
| Before Application | 10 cc in 4 minutes | 2.5 cc/minute |
| After Application | 0.5 cc in 10 minutes | 0.05 cc/minute |
| Specific Change | – – | 2.45 cc/minute |
| % Change | – – | 98% improvement |
C. Water Chlorides
Total chlorides in the bridge deck were measured using the top 1 inch of a ½ inch diameter core taken from the curb. The sample was pulverized, dissolved in acid, and the weight per cent chloride ion was measured using a calibrated electrode measuring the solutions electrical potential. The sample contained .032 weight per cent chloride ion or 320 PPM. This is a low level – normally 800 PPM is the level associated with rebar corrosion. Therefore, no further tests were performed.
Normally the application of SURTREAT TPS II reduces the amount of water soluble chlorides by 50% and water soluble chlorides account for about 50% of total chlorides.
D. Depth of Carbonation & pH
The pH of ½ inch dia. cores taken from the bridge deck was measured using a multi range indicator dye mixture. The test taken before SURTREAT® showed a depth of carbonation of ¼ – ½ inch or a pH of 8-9 versus a pH of 12 below the ½ inch depth. After application the pH in the carbonated area had increased to 11.5. This form of deterioration had been reversed.
E. Acid Reactivity
Acid Reactivity of the concrete bridge deck curb was measured by placing a drop of concentrated hydrochloric acid on the surface and observing the reaction. Before SURTREAT® the acid gave a vigorous foaming reaction and etched the concrete surface. After SURTREAT®, the acid drop did not foam, etch, or react with the concrete surface in any way.
F. Silver Chloride Half Cell Corrosion Rebar Potential
The corrosion potential of the steel rebars embedded in the ends of the bridge deck parapet (which holds the guard rail cable) was measured before and after the application of Surtreat®. If the silver chloride half cell potential is above 200 mV, then corrosion may be occurring. The higher the negative value – the greater the corrosion potential. Measurements were made on all 4 parapet ends on each of the 2 steel bars before and after the application of SURTREAT®.
| LOCATION | Before Application Negative mV Average | After Application Negative mV Average |
| NW – TOP | 235 | 150 |
| NW – BOTTOM | 160 | 130 |
| NE – TOP | 217 | 127 |
| NE – BOTTOM | 50 | 63 |
| SW – TOP | 165 | 96 |
| SW – BOTTOM | 435 | 382 |
| SE – TOP | 285 | 150 |
| SE – BOTTOM | 400 | 247 |
| AVERAGE | 243 | 168 |
The above measurements indicate that the application of SURTREAT® took the embedded steel rebars from a corrosive to a non-corrosive electrochemical condition.
G. Water Repellency
SURTREAT® inhibits water penetration by sealing porosity. SURTREAT® inhibits water penetration by reducing surface tension so that water will not cling to or “wet” the concrete surface.
The value of the rubber membrane is obvious. It creates an impermeable barrier preventing salt water from the road surface from contaminating the concrete deck. The SURTREAT® TPS II will inhibit any corrosive potential prior to the membrane installation or if the membrane were compromised.
Project 2 Year Updated Test Results
Concrete Strength
The concrete strength was again measured using the CAPO Pull Out Method as previously described.
| Condition – 1996 | Pull Out Force (KN) | Equivalent Compressive Strength (psi) |
| Before Application | 22.3 | 3215 |
| After Application | 32.8 | 5038 |
| Increase | 10.5 | 1823* |
| Condition – 1998 | ||
| After 2 Years | 34.0 | 5429 |
| Total Increase | 11.7 | 2214* |
*Please note the very significant increase in compressive strength. This increase is consistent with our experience that the benefits of a SURTREAT® application increase over time as the chemical reaction continues to progress.
Water Permeability
Measures the susceptibility of the concrete to absorb a certain amount of water under pressure in a specific period of time.
| Condition – 1996 | Specific Measurement | Rate in cc/min |
| Before Application | 10 cc in 4 minutes | 2.5 cc/minute |
| After Application | 0.5 cc in 10 minutes | 0.05 cc/minute |
| Specific Change |
|
2.45 cc/minute |
| % Change |
|
98% improvement |
| Condition – 1998 |
|
|
| After 2 Years | 1 cc in 10 minutes | 0.1 cc/minute |
| % Change |
|
96% improvement |
Testing showed that the surface retained the ability to resist water penetration. The porosity was reduced and remained virtually unchanged (measured at a hydrostatic pressure of 30 psi).
pH Testing
The pH was tested by applying indicator dye to a freshly extracted concrete core.
|
Condition – 1996 |
pH Measured |
|
Before Treatment |
8-9 at ¼ – ½ inch depth |
|
After Treatment |
11.5 at ¼ – ½ inch depth |
|
After 2 years |
10 – 11 at ¼ – ½ inch depth |
Acid Reactivity
This was measured by placing a drop of concentrated hydrochloric acid on the surface and observing the reaction.
1996: Before SURTREAT® the acid gave a vigorous foaming reaction and etched the concrete surface.
After SURTREAT®, the acid drop did not foam, etch, or react with the concrete surface in any way.
1998: After 2 years there was no reaction and no surface etching.
Chloride Ion Content
The Chloride Ion Content was established in 1996 to be 0.032 weight percent or 320 PPM. Because this is significantly below the 800 PPM level associated with chloride induced corrosion, it was determined that no follow-up testing was required in 1998.
Typically, SURTREAT® reduces water soluble chlorides by appx 50% in the top 1-2 inches of concrete surface.
Water Repellency
This was tested by applying water to the SURTREAT® treated concrete surface.
1996: After SURTREAT® test results showed excellent water repellency.
1998: After 2 years excellent water repellency – no surface wetting.
SURTREAT® is also acting as an excellent safeguard against dirt and grime – keeping the bridge clean. This accounts for increased reflective properties, thus greatly improving night visibility of the structure especially when driving conditions are poor (rain or snow).
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SURTREAT® works across a wide variety of industries. Our products renew, restore, and repair even the toughest structural damage.
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