New Jersey

Department of Transportation

Standard Specifications

for Road and Bridge Construction

2007

NJDOT C-5 – Static Segregation of Hardened Self-Consolidating
Concrete Cylinders

1. Scope. This test method is used for determining the static segregation resistance (stability) of SCC using hardened test specimens. This method provides a visual assessment of static segregation resistance of SCC using a Hardened Visual Stability Index (HVSI) rating to evaluate molded or cored hardened concrete cylinders cut lengthwise in 2.
   
   
2. Apparatus. Use the following apparatus:
   
   
   1. 4 × 8-inch cylinder molds for casting concrete test specimens shall conform to the requirements of AASHTO M 205.
   2. Hand-held wood or metal float or trowel.
   3. A saw with a diamond or silicon-carbide cutting edge and capable of cutting specimens without excessive heating or shock.
   4. A suitable container for filling specimen molds with SCC. Experience has shown pails and plastic cylinder molds to be suitable containers.
   
   
3. Procedure. Perform the following steps:
   
   
   1. Sample plastic SCC according to AASHTO T 141.
   2. Mold two 4 × 8-inch test specimens as near as practical to the place where they are to be stored. If it is not practical to mold the specimens where they will be stored, move them to the place of storage immediately after strike off. Place molds on a rigid surface free from vibration and other disturbances. Ensure that the supporting surface is level to within 0.25 inch per foot.
   3. Fill the specimen molds in 1 lift poured using a suitable container without vibration, rodding, or tapping.
   4. Strike off the surface of the concrete level with the top of the mold using a float or trowel.
   5. Immediately after molding and finishing, cap the specimens with a plastic cylinder lid or cover with a plastic bag. Store for a period up to 24 hours at a minimum temperature of 60 °F.
   6. Before subjecting the specimens to sawing, ensure that they have been cured for a minimum curing period of 24 hours or have attained a minimum compressive strength of 900 pounds per square inch according to AASHTO T 22.
   7. Saw specimens lengthwise down the center. If a specimen cannot be satisfactorily sawed smooth due to lack of curing, then do not disturb the remaining specimens for an additional minimum curing period of 24 hours.
   8. Make a visual assessment of the cut planes of the hardened concrete cylinder or core using the criteria in Table C-5-1. Wet the cut planes to facilitate visual inspection.
   
   

   Table C-5-1 – HVSI Specimens Rating Criteria
   Rating	Criteria
   0 stable	No mortar layer at the top of the cut plane and no variance in size and percent area of coarse aggregate distribution from top to bottom.
   1 stable	No mortar layer at the top of the cut plane but slight variance in size and percent area of coarse aggregate distribution from top to bottom.
   2 unstable	Slight mortar layer, less than 1 inch tall, at the top of the cut plane and distinct variance in size and percent area of coarse aggregate distribution from top to bottom.
   3 unstable	Clearly segregated as evidenced by a mortar layer greater than 1 inch tall and/or considerable variance in size and percent area of coarse aggregate distribution from top to bottom.

   
   
4. Report. Report the following:
   
   
   1. Identification number.
   2. Location of concrete represented.
   3. Date and time of molding.
   4. HVSI rating for each hardened specimen.
   5. Results of any other tests on the fresh concrete.