Green Canvas Expansive Component – Is a specialty concrete component classified by type based on the chemical mechanism used to obtain expansion in the concrete matrix during the curing process. Structure design, concrete mix design, and placement guidance is provided by the American Concrete Institute (ACI) document ACI 223 “Guide Practice for the Use of Shrinkage Compensating Concrete” and compliance and quality assurance can be measured by standard ASTM tests and procedures.

APPLICATION

BENEFITS

Benefits of Green Canvas Expansive Concrete –

A calcium hydroxide platelet system, such as Green Canvas, for producing SCC has all of the above benefits plus additional benefits that distinguish it from other types of SCC, including:
• Material costs most economical when compared with other methods of producing SCC.
• Shipping costs for Green Canvas Expansive Concrete is much less than the shipping costs of shrinkage compensating cement.
• Material and shipping costs for Green Canvas is less than the comparable costs of other components due to lower dosage rates.
• GreenCanvas can be shipped in bags or pails at the exact required dosage per cubic yard of concrete resulting in the highest quality control available.
• Green Canvas does not change the physical or handling characteristics of the concrete mix making it very user friendly for the ready mix supplier and the placing / finishing contractor.
• Being a cementitious material Green Canvas increases the compressive strength of concrete when it is added to a standard mix design.
• Being a cementitious material the MSDS sheet on GreenCanvas is very similar to that of Portland cement thereby eliminating the concerns of handling unknown chemicals.
 

JOINTS – SCC made with Green Umbrella Green Canvas allows the design engineer and the contractor to eliminate many of the contraction joints associated with regular concrete design and construction. Expansion joints between adjacent placements can often be eliminated by larger monolithic designs. Expansion joints placed for thermal expansion of linear elements are determined by thermal considerations that are not changed by the use of SCC.

DOSAGE – is a function of the required expansion as determined and specified by the design engineer based on the requirements of ACI 223. ASTM C-878 tests are performed by an independent testing laboratory in order to determine the proper mix design to supply the specified expansion. The mix design is then submitted for approval in accordance with project contract documents. A general rule for most projects is to add 8% -10% of the cementitious material in the mix, by weight, of Green Canvas Expansive Concrete to a standard mix design, thereby allowing use of ACI's statistical history method for mix design approval. If GreenCanvas Expansive Concrete is substituted for an equivalent amount of cementitious material in a mix design, strength test of a trial mix may have to be performed to document strength requirements of the mix.

SHELF LIFE – Quality Assurance, TQM, and packaging procedures require that we custom manufacture GreenCanvas for each shipment. The shelf-life of is less than that of cement. Recommendations are to use all material within two months of receipt in bulk or paper bags. GreenCanvas in pails can be stored from six months to one and one half years. Paper bags are not biodegradable, therefore care should be taken to keep all bags out of the concrete mix.

COSTS – vary considerably depending on the type and location of the project. While adding Green Canvas to the concrete mix does increase the price of the concrete, the ability to place larger monolithic pours eliminates many contraction and expansion joints.

The American Concrete Institute defines shrinkage compensating (Expansive) concrete as a concrete that, when properly restrained by reinforcement or other means, expands an amount equal to, or slightly greater than, the anticipated drying-shrinkage. Subsequent drying-shrinkage will reduce these expansive strains, but, ideally, a residual expansion will remain in the concrete, thereby eliminating shrinkage cracking. (ACI 223 – 2010)
Shrinkage Compensation - A component is added to a standard concrete mix by the ready mix supplier or contractor, to provide a Type G SCC in accordance with ACI 223. Green Umbrella Shrinkage Compensation achieves shrinkage compensation through the formation of calcium hydroxide platelets within the concrete matrix.

PROJECT EXAMPLE (Size 150' x 150' / 22,500SF)

Standard Slab (WITHOUT Green Canvas Expansive Concrete):

1. A 6" non-reinforced Portland cement concrete floor slab measuring 150' x 150', 22,500 sq. ft., will typically have 3,300 linear feet of control joints, and 144 independent panels.
2. This slab will experience curling at the control joints, panel movement, and joint deterioration due to movement.
3. Multiple concrete placements are required.
4. This slab will have many joints that require care and maintenance, and have a limited service life.

Shrinkage Compensating or Expansive Slab (Green Canvas Expansive Concrete):

1. A 6" reinforced slab measuring 150' x 150', 22,500 sq. ft., with #4 rebar, compensated for shrinkage with Green Canvas, will have NO CONTROL JOINTS, and thus, no individual panel movement.
2. The slab will function as a single unit and provide positive load transfer across the concrete slab. There is a saving of 3,300 linear feet of jointing material and construction placement.
3. The slab can be accomplished with a single concrete placement (the entire 22,500 sq.ft.).
4. There will be far fewer joints, it will require less care and maintenance and will provide for greatly extended service life with lowest life cycle cost.

Why is Green Canvas so beneficial? Take a look at the following diagram as it illustrates the potential problems with a standard slab and how those are corrected with the use of Green Umbrella™ Green Canvas.

click to enlarge

 DOWNLOADS

Product Sales Sheet

White Papers

MSDS

Spec