Time and Temperature Guide to Reopen Roadway to Traffic Using Utilibond in Cold Weather

 

Reinstatement at 70°F (21°F) - 30 Minutes to safely reopen the roadway to traffic

Cores may be safely reinstated with Utilibond and the roadway safely reopened to traffic in 30 minutes when the temperature of the pavement slab, core and bonding materials, including mixing water immediately before placement, are at a minimum of 70°F (21°C). At that temperature the bond strength of a typical 18-inch diameter core, 8-inches deep will be capable of supporting a wheel load of at least 30,000 lbs or 3 times the AASHTO H-25 Standard, in 30 minutes after application, and the roadway can be safely reopened to traffic at that time.

 

Reinstatement at 50°F (10°F) - 60-90 minutes to safely reopen the roadway to traffic

Cores may be safely reinstated with Utilibond and the roadway safely reopened to traffic in 60-90 minutes when the temperature of the pavement slab, core and bonding materials, including mixing water immediately before placement, are at a minimum of 50°F (10°C). At that temperature the bond strength of a typical 18-inch diameter core, 8-inches deep will be capable of supporting a wheel load of at least 30,000 lbs or 3 times the AASHTO H-25 Standard, in 60-90 minutes after application, and the roadway can be safely reopened to traffic at that time. Use of Utilibond - XL will reduce set times.

 

Reinstatement at temperatures BELOW 50°F (10°C)

While reinstatement of cores can be performed with Utilibond at temperatures as low as 40°F (5°C) because of the proximity to freezing temperatures and the danger of frost crystals forming at the bonding interface, it is required that a source of external heat, such as a Utilicor Core Heater, be employed to raise the surface temperatures of both the core and the surrounding pavement to 70°F (21°C) at which temperature the bond strength of a typical 18-inch diameter core, 8-inches deep will be capable of supporting a wheel load of at least 30,000 lbs or 3 times the AASHTO H-25 Standard, in 30 minutes after application, and the roadway can be safely reopened to traffic at that time. Use of Utilibond - XL will reduce set times.

 

Reinstatement at temperatures BELOW FREEZING - 32°F (0°C)

The Core Heating procedure can also be successfully employed to facilitate core reinstatement with Utilibond at temperatures below freezing, providing that the duration and application of external heat from an approved Core Heater is sufficient to raise the temperature of both the core and the surrounding pavement to approximately 70°F (21°C) and the bonding materials, including water, immediately before placement , are at the same minimum temperature of 70°F (21°C)

 

As might be anticipated, the duration of heating required to achieve these results at below freezing temperatures, using an approved core heater, will vary inversely with the ambient temperature of the pavement but should not exceed 15-20 minutes in normal circumstances at a temperature down to 10°F (-21°C).

 

Once the surface temperature of the core and the pavement reach a sustainable 70°F (21°C), normal core reinstatement procedures can be employed and the bond strength of a typical 18-inch diameter core, 8-inches deep will be capable of supporting a wheel load of at least 30,000 lbs or 3 times the AASHTO H-25 Standard, in 30 minutes after application, and the roadway can be safely reopened to traffic at that time.

Instructions for Core Heater

Utilibond - XL Cold Weather Accelerant

Testing completed in laboratory environment.

Final set times may vary in field conditions. 

 

Cold Weather Core Reinstatement Process

Before you begin, make sure the core is dry fitted properly, as per warm weather reinstatement process.

Place the core heater base in the hole and connect heater-blower to base unit and place core on the base.

Place core cover on top of the Base, and open vents on top of core cover.

 

Ignite blower and position into baffle.

Check the temperature occasionally with a non-contact infrared temperature sensor.

When the surfaces of the core reaches at least 70° F, the core reinstatement process can begin.

 

Note: Make sure the Utilibond powder is stored in a warm location, and use warm water to mix with.

Remove the core heater and place the core in the opening, which will keep the core warm while mixing the Utilibond. 

Once ready, remove core, pour in mixed Utilibond, and reinstate the core as per normal procedure.

The reinstated core will begin to set up within 15-20 minutes.

 

Take intermittent temperature readings to better gauge set time.

At 70° F ambient temperatures Utilibond will reach final strength gain in 30 minutes.

Final core reinstated, and after 30 minutes the road can be reopened to traffic.

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