UNH In-situ Slab Testing Program

In-situ Testing Program at Rochester, NH Turnkey Facility

Purpose of the In-situ Testing: To expose six (6) full scale HPC slabs to actual road and environmental conditions

Size: 4 feet wide by 14 feet long by 8.5 inches thick

Three HPC mix designs (FHWA proposed HPC definitions)

Each mix design had a deck slab specimen reinforced with:

Bare concrete wearing surface

Single 10' - 6" span

Location - Photos: Turnkey Landfill Facility; Waste Management, Inc.; Rochester, New Hampshire

Duration and Loadings: Placed: September, 1994; Removed: May, 1995; Loading: Equivalent to 1 yr I-95 truck loading; Max. Load approx. 120 kips

Some of the Tests Performed: ASTN C39: Compressive strength - cylynders - 1,3,5,7,14,28,56 days; ASTM C231: Air content; ASTM C469: Static Modulus of Elasticity; ASTM C666: Resistance to rapid freezing and thawing; ASTM C672: Scaling resistance of surfaces exposed to deicing chemicals; ASTM C876: Half-cell potentials of uncoated reinforcing steel in concrete; ASTM C1074: Estimate concrete strength by the maturity method; ASTM C1202: Electrical indication of ability to resist chloride ion pentration; Water content of fresh concrete using microwave test; Estimate natural frequencies of the decks by a heel drop test

Test Performed	Mix 1	Mix 2	Mix 3
Unit Weight	142.2 (lbs/ft3)	139.6 (lbs/ft3)	142.2 (lbs/ft3)
Compressive Strength - Cylinders	8910 psi - 28 days 9920 psi - 56 days	7220 psi - 28 days 8330 psi - 56 days	9700 psi - 28 days 10160 psi - 56 days
Compressive Strength - Cores	7690 psi - 28 days 9510 psi - 56 days	6430 psi - 28 days 7480 psi - 56 days	8400 psi - 28 days 9510 psi - 56 days
Air Content	6.1%	7.0%	5.5%
Static Modulus Cores - 510 days	4950 ksi	4260 ksi	4110 ksi
Freeze - Thaw (% wgt loss after 300 cycles)	3.18%	2.28%	N.A. (equipment problem)
Scaling Resistance Rating 50 cycles - avg. of 6 observations	1 - 5 cycles 3 - 15 cycles 3.73 - 50 cycles	1 - 5 cycles 3 - 15 cycles 2.9 - 50 cycles	0 - 5 cycles 2 - 15 cycles 2.08 - 50 cycles
Chloride Ion Pentration	1184 - 56 days 1020 - 1 year	1184 - 56 days 625 - 1 year	896 - 56 days 641 - 1 year
Water Cement Ratio	0.418	0.441	0.412
Est. Natural Freq. Epoxy-coated Bars	33.0 Hz - Dec. 1994 27.5 Hz - Apr. 1995	38.0 Hz - Dec. 1994 24.5 Hz - Apr. 1995	34.8 Hz - Dec. 1994 30.3 Hz - Apr. 1995
Est. Natural Freq. Uncoated Bars	33.0 Hz - Dec. 1994 28.8 Hz - Apr. 1995	30.5 Hz - Dec. 1994 24.0 Hz - Apr. 1995	32.8 Hz - Dec. 1994 30.0 Hz - Apr. 1995