 |
|
|
|
|
|
Home |
New |
Services |
Us |
|
|
|
|
|
|
Home |
New |
Services |
Us |
|
|
 |
 |
|
 “SCC as defined by ACI (American Concrete Institute) committee 223”…. “An expansive cement concrete which when properly restrained by reinforcement or other means, will expand 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.” For slabs-on-grade minimum shrinkage reinforcement in accordance with ACI 223 shall be provided. For steel reinforcing bars of fabricated steel mats this is shall be 0.15% by cross sectional area of concrete. Reinforcement will be located in the upper half of the slab with cover as recommended by ACI 318. Reinforcing shall be supported by wire or plastic chairs manufactured for this use. Construction joints shall be in accordnce with ACI 223. Using shrinkage compensating cement, ASTM C-845 Type K cement, has been the standard method of making shrinkage compensating concrete for decades. The shrinkage compensating concrete industry was revolutionized when ACI 223 adopted the use of components. CompCon is a Type G component that meets the requirements for shrinkage compensating concrete while greatly reducing the cost of SCC supply, placement, finishing, and curing. Standard methods and techniques can be used during all stages of concrete placement. The amount of expansion is controlled by the amount of CompCon added to concrete mix. The cementitious factor remains the same as required for the specified strength. Expansion may be easily verified in the field by a simple test using a clear plastic 10 oz water cup. Fill the cup with the concrete being placed, cover with plastic, wet cloth,or wet sponge and allow to stand for 24-48 hours. Within this period, the cup will crack, indicating that expansive action is occurring due to the CompCon in the mix. This is not to be construed as an indicator of the amount of restrained expansion (RE), but merely as a means of verification of expansion occurring. For an accurate determination of RE, an ASTM C-878 test must be conducted using the in-field concrete. CompCon may be used with most ASTM C-150 cements, including Types I, II, III, V and slag cement. CompCon may also be used along with other cementitious materials, such as fly ash and silica fume. In such cases, the total cementitious should have a minimum of 450 lbs/cu.yd. of Portland cement, unless tests prove that a lower Portland cement content is satisfactory. Where there are sulfate conditions, CompCon may be used with Type V or Type II cement, a low W/C ratio, plus a low-carbon fly ash. In the case of the latter, tests should be run to determine the suitability of the fly ash. In both cases, it is recommended that tests be conducted to assure the desired resistance to sulfates. | What is CompCon | Chemistry | Concrete Characteristics | Facts about SCC | CompCon & Floor Slabs | Pre-Stressed | Links | | Return Home | Products | Projects | What's New | Our Services | Contact Us | |
||
 |
 |