In the case of HSC and VHSC, the initial drying shrinkage of VHSC was relatively large, but, after 30 days, it became similar.
UHSC demonstrates a much earlier cracking age and a much higher strain level than HSC and VHSC. In addition, a more abrupt cracking tendency was observed for the concrete with a higher strength level.
In the case of HSC and VHSC, the crack occurred at the 75~80% level of splitting tensile strength, whereas, in the case of UHSC, the restrained tensile stress at cracking reached the full tensile strength.
The following conclusions were drawn from the results of the restrained and unrestrained shrinkage tests of HSC, VHSC, and UHSC.
The compressive strengths of UHSC were 47 MPa and 27 MPa higher than HSC and VHSC with W/B of 30% and 25%, respectively, but there was no significant difference in the tensile strength.
Caption: Figure 9: Average strain in the steel ring of HSC, VHSC, and UHSC (35 mm concrete ring).
"PozzoSlag provides significant value by allowing customers to produce high grade concrete while increasing profits, and to recycle coal fly ash, which may otherwise be dumped in landfills and ponds," adds David Waxman, VHSC principal.
VHSC has also secured approval for Texas Department of Transportation work, including Federal Highway Administration-funded projects, plus public works contracts in Austin, Dallas and Houston.
Through November 2012, VHSC tested several generations of PozzoStag in its tab and through demonstrations with Texas ready mixed and precast concrete producers.
VHSC has set up production on 10 acres in Jewett, Texas, which lies off Interstate 45 about midway to Houston from Dallas.
Caption: With a 1,500-ten silo and load out VHSC formally introduced PozzoSlag 1.2 in late 2012, building a charter customer base with ready nflxed and manufactured-concrete producers in Dallas and Austin.
Caption: VHSC's reactor--a customized rotary mill--and proprietary additive package are patent pending, along with the process that converts Class F ash to slag-like binder.