Dallas, Texas, May - June 2008
The IH-30 Bridge over Loop 12 west of Dallas, Texas contains
approximately 1,000 cubic yards of TXI Hydromax internally cured
concrete mix. In May and June of 2008, Austin Bridge and Road under the
supervision of TxDOT Dallas District, pumped on three different
occasions, a total of approximately 1,000 cubic yards of TXI’s
internal curing concrete mix on the IH-30 bridge deck.
TXI Hydromax contains a medium gradation of ASTM C 330
rotary-kiln-produced expanded shale aggregate that replaces a portion of
the coarse and fine aggregates in the concrete mix. Because of the well
known properties of absorption, the expanded shale aggregate releases
moisture back into the mix during the curing or setting period further
enhancing the compressive strengths and durability of the concrete.
All the pours were started in the early morning hours before sunrise and
finished by 8 AM or 9 AM.
The required flexural strength was obtained in 7 days.
TxDOT Lab compressive strengths for the trial mix design averaged 4,690
PSI in 7 days.
The required 4,000 PSI 28 day compressive strengths were met or
surpassed by as much as 1,000 PSI in 7 days.
28 day strengths averaged over 6,000 PSI on one set of cylinders.
One cylinder broke over 7,000 PSI after 56 days.
Pour conditions at times experienced 25 mph to 35 mph winds on the
elevated bridge deck. Ambient temperatures ranged from high 90’s
to low 70’s that are typical of late spring and early summer for
the North Texas Region. TXI’s Hydromax experienced very minimal
cracking in the bridge deck pours observed both during and after pour
events.
