by tom kuennenRead More
From Rice University, Houston … Bringing order to disorder is key to making stronger and greener cement and concrete. In National Science Foundation and U.S. Department of Energy-backed research, Rice University scientists have decoded the kinetic properties of cement and developed a way to “program” the microscopic, semicrystalline particles within. The process turns particles from disordered clumps into regimented cubes, or spheres that combine to make the material less porous and more durable.Read More
One of the largest problems ready mixed producers face every day on the job is the quality and consistency of concrete field testing. Ask if they have experienced poor quality testing then brace yourself for stories of uncalibrated machines, uncovered cylinders, incorrect curing temperatures and uncertified technicians.Read More
“Crushable” concrete for better protection against terrorists … improved designs for precast rockfall barriers … corrosion of precast concrete barrier connections … lightweight, high-performance, self-consolidating concrete for bulb-T beams. They’re all part of new research presented earlier this year during the 94th annual Transportation Research Board annual meeting, which drew 12,000-plus design, engineering and allied professionals to Washington, D.C.Read More
Replacement of recycled concrete aggregate (RCA) for natural coarse aggregate by up to 45 percent by volume had no significant effects on any of the concrete properties studied, indicating high-quality RCA can be used as a replacement for a portion of the coarse natural aggregates in new portland cement concrete pavements. That’s what Haifang Wen, Ph.D., P.E., Washington State University; David I. McLean, Ph.D., P.E., Colorado State University; and, Kim Willoughby, Washington State DOT, report in their 2015 TRB paper, Evaluation of Recycled Concrete as Aggregates in New Concrete Pavements.Read More
A refined self-consolidating concrete (SCC) mix was developed to achieve the high workability needed for faster concrete discharge and finish, and attain the Florida Department of Transportation six-hour strength requirement of 2,200 psi (15 MPa) for concrete slab replacements, report Jamshid Armaghani, Ph.D., P.E., Global Sustainable Solutions, Gainesville, Fla.; Kamal Tawfiq, Ph.D., P.E., and Steven Squillacote, FAMU-FSU College of Engineering, Tallahassee; and, Michael Bergin, P.E., State Materials Office, Florida DOT-Gainesville, in their 2015 TRB paper, Accelerating Slab Replacement Using Self-Consolidating Concrete.
Research in Mississippi shows that portland cement/limestone blends (PLC) result in notable compressive strength improvements in mixtures with high Class C fly ash replacement versus conventional Type I portland cement, say Jay Shannon and Dr. Isaac L. Howard, P.E., Mississippi State University, and V. Tim Cost, P.E., F.ACI, and Wayne M. Wilson, P.E., Holcim (US) Inc., in their 2015 TRB paper, Benefits of Portland-Limestone Cement for Concrete with Rounded Gravel Aggregates and Higher Fly Ash Replacement Rates.
New Purdue University research says ‘yes’
Glow-in-the-dark concrete took the stage with new research in self-consolidating concrete, portland cement/limestone blends, and recycled concrete aggregates in ready mixed concrete, and it’s all illuminating the future of cast-in-place.
By Tom Kuennen
Roller-compacted concrete (RCC), followed by diamond grinding to smooth the surface, is the smart choice for rebuilding rural roads damaged by energy development truck traffic in Arkansas, according to new research presented at the 93rd annual meeting of the Transportation Research Board earlier this year in Washington, D.C.Read More