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Ground Thaw


 


 

How It Works

The versatile Ground Heater® – solves cold weather construction problems! Ground Heaters®‘ dry, radiant, hydronic heat is economical and easy to use!

  • Thaw frozen ground for excavation and concrete placements
  • Thaw up to 1 foot deep per day!
  • Accurately quote winter construction jobs
  • Deliver projects on time
  • Keep crews and equipment working all winter
  • Protect exposed footings from frost heaving
  • No need to build temporary roads.. adjacent ground stays frozen
  • Cure concrete – achieve required strength gain sooner
  • Quote projects accurately
  • Keep projects on schedule
  • Keep crews and equipment working all winter
  • Avoid risk and expense of frozen concrete
  • No expensive enclosures to build

 

Thawing

 

Problem:
Ice in the soil! 		Know Your Dirt!  Ice  Content of Frozen Soils

Gravel
5 to 7 lbs.
in 1 cu. ft.		 Sand
14 to 18 lbs.
in 1 cu. ft.		 Clay
16 to 22 lbs.
in 1 cu. ft.		 Silt
15 to 52 lbs.
in 1 cu. ft.
Up to 1,001
Btu’s required
to melt ice		 Up to 2,574
Btu’s required
to melt ice		 Up to 3,146
Btu’s required
to melt ice		 Up to 7,436
Btu’s required
to melt ice
Melting ice requires 143 Btu’s per pound!

Frost Facts

  • Soil does not freeze
  • Water in soil freezes
  • Ice binds soil
  • Melting ice requires 143 Btu’s per pound!
Best Solution:

Ground Heater®

 Ground Heater® System

94% of the heat is conducted into frozen ground!

 

  • Thaws at a fast rate – typically 1 ft. deep per day
  • Achieves up to 10′ thaw depth per application
  • No temporary enclosure to build
  • Uses fuel efficiently; fuel costs per cu. ft. thawed:
    = less than 2?
    = $1.10
  • Requires minimal supervision
  • Utilizes BTU’s efficiently with minimal heat loss

 
Old Solution:

Hot Air.

 Hot Air System

Only 15% of the heat is conducted into the frozen ground!
  • Limited thaw depth
  • Requires building costly temporary enclosures
  • Requires noisy propane heaters
  • Creates outrageous propane bills
  • Emits noxious fumes into enclosure
  • Requires constant supervision

 
Thaw Cost Comparison

 

Thawing 6,000 sq. ft., 3 ft. deep

Hot Air 

Ground Heater 

Own Rent
Time 25 days 3 days 3 days
Equipment/labor/materials cost $4,934 $913 $1,860
Fuel Cost $19,800 $390 $390
Total job cost $24,734 $662 $1,568
Cost/cu. ft $1.37? 8.7? 16.7?
NOTE: Figures above are based on average rates/costs. Actual rates/cost incurred may vary depending upon geographical location.
Ground Heater®   out-performs hot air!
Thawing 6,000 sq. ft., 3 ft. deep
Time 8:1
Fuel Cost 50:1
Overall Cost 14:1

 
Ground Heater®System Setup

  1. Prepare Site
    Scrape snow and ice from thaw site.
  2. Position Heat Transfer Hose
    Space hose 2 feet on center over thaw site area. A closed system, only heat goes into ground.
  3. Lay Poly Vapor Barrier
    Place minimum 3 mil poly vapor barrier to contain water vapor.

    • Prevents loss of heat
    • Keeps soil moist for better heat conduction
    • Keeps hoses and blankets clean
  4. Place Insulation Blankets
    Prevent heat loss and direct heat into ground. Requires 2 to 3 layers of high R value blankets.

 
Benefits!
  • Thaw fast – typically 1 foot deep/ day!
  • Thaw cheap – as low as 9.7?/cu. ft.
  • Thaw deep – up to 10 feet/application
  • Thaw easy – no enclosures to build; set up is simple
  • Thaw large areas – up to 18,000 sq. ft./application
  • Thaw safe –   certified in the US and Canada

NOTE: Figures above are based on average rates/costs. Actual
rates/cost incurred may vary depending upon geographical location.

 

Curing

 

Problem Cold temperatures slow speed of concrete’s cure, causing cost increases and schedule delays.

 

Best Solution:

Use a Ground Heater     to accelerate the cure.

A Ground Heater  raises concrete to ideal curing temperature (65°-75°F), greatly reducing costs and delays.

Fact #1:

Hydration Reaction

   Fact #2:

Temperature

   Fact #3:

Speed

  
Cement chemically reacts with water to produce calcium silicate hydrate… the chemical compound that makes concrete hard and strong. Temperature mainly determines the speed of thishydration reaction. The speed of the hydration reaction determines how long it takes for concrete to set and develop strength. The speed of the hydration reaction is mostly determined by the temperature of the concrete.

 

 

 

Concrete Curing Process

 

Aggregate & Paste Plastic Phase.
Concrete is placed.
Cold temperatures delay initial set and increase the risk of concrete freezing.

Temperature vs Time to Initial Set

 
Initial Set Set Phase.
Finishing operations are completed.
Cold temperatures delay final set and increase the risk of concrete freezing.
Concrete must reach 500 psi before it can withstand a freezing cycle.

Temperature vs Time to Reach 500 psi
Final Set Hardened Phase.
Curing measures are implemented and strength development begins.
Cold temperatures delay strength gain. Concrete must reach 75% design  strength to strip forms & withstand load.
Temperature vs Time to Reach 75% Design Strength
Hard Rigid Concrete
Benefits
  • Cure fast – achieve initial set in 2-6 hours
  • Cure all placements – flexible hose allows any configuration
  • Cure easy – no enclosures to build; set up is simple
  • Cure large areas – up to 45,000 sq. ft./application
  • Cure safe – certified in the U.S. and Canada

 

 

 

Slab on Grade

 
1. Preheat ground 2. Remove insulation & hoses 3. Place concrete on warm ground 4. Maintains slab at 65°-75°F

 

 

Poured walls or Columns

 

1. Preheat forms, cover with insulation 2. Pour 75° concrete into forms 3. Ground Heater maintains 65°-75°F concrete for curing period

 

 

Elevated Slab

 

Ground Heater heating elevated slab Cross-section view Ground Heater maintains 65°-75°F concrete for curing period