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NOTES FOR SLABS ON GRADE

1)  WATER / CEMENT RATIO OF APPROXIMATELY .50 AND UP TO A 5" SLUMP.

2)  ENSURE THAT GRADE AND FORMS ARE FREE FROM FROST.

3)  DAMPEN SUBGRADE AND FORMS, BUT NO FREE STANDING WATER OR MUDDY SPOTS.

4)  VAPOR BARRIERS: 

    :SHEETS HAVE 6" OVERLAP AND VAPOR TIGHT

    :LAYER OF 4" GRANULAR FILL IS RECOMMENDED ON TOP OF    BARRIER TO PROTECT BARRIER AND REDUCE SHRINKAGE PROBLEMS.

5) REINFORCEMENT AT MID-DEPTH

6)  PARTS OF CONCRETE WITH THE MOST WATER WILL SHRINK THE  MOST AND BE

THE WEAKEST---WILL SETTLE MORE AND CAUSE "BIRD BATHS" & CURLING

7) DON'T FLOAT OR TROWEL THE SLAB UNTIL BLEEDING HAS STOPPED AND CONCRETE

IS FIRM ENOUGH TO PERMIT WORKER TO WALK ON WITHOUT LEAVING FOOTPRINTS MORE THAN 1/4" DEEP.

8) DON'T WORK BLEED WATER INTO SURFACE---LET EVAPORATE---WILL RESULT IN LOWER WATER / CEMENT RATIO IN SLAB.

:WORKING BLEED WATER INTO SLAB WILL RESULT IN EXCESSIVE SURFACE SHRINKAGE.

9) IF YOU NEED TO REMOVE BLEED WATER, DRAG WATER HOSES ACROSS WHEN STIFF ENOUGH ONLY TO REMOVE WATER…NOT THE CONCRETE.

10) FLOAT WHEN BLEED WATER SHEEN IS GONE, AND TROWEL IMMEDIATELY FOLLOWING FLOATING.

11) CURING MUST BEGIN IMMEDIATELY FOLLOWING FINISHING.

:HYDRATION DEPENDS ON TIME AND TEMPERATURE, BUT REQUIRES MOISTURE TO BE PRESENT.

:THE LONGER IT HARDENS (CURES), THE STRONGER AND MORE DURABLE IT BECOMES.

12) PLASTIC SHRINKAGE OCCURS WHEN THE SLAB SURFACE IS DRYING FASTER THAN THE BLEED WATER IS COMING TO THE SURFACE.