Photo courtesy of PERI, by Helmut Schugg

Innovations in Concrete

New Views on a Time-Tested Material

Concrete is everywhere in our world today. We drive down concrete streets, span rivers with concrete bridges, work in concrete high-rises, even prepare the evening’s meal on concrete countertops. It’s the material that has formed the foundations of society for hundreds of generations. But don’t let concrete’s age fool you—this old dog definitely can learn new tricks.

Going green

The movement toward sustainable design and construction is undeniable, and concrete is helping architects, engineers and contractors go green on all kinds of projects: museums, offices, schools, performance halls, and libraries, just to name a few. How does concrete build green? Its high thermal mass helps optimize energy performance of finished structures. Recycled materials and industrial byproducts like slag, fly ash and silica fume are integrated into concrete, bringing benefits including increased durability and strength. Concrete is manufactured locally, minimizing material transport costs and sustaining local economies. And concrete builds structures that last.

Photo courtesy of the Portland Cement Company

On track

Recent research by the Portland Cement Association (PCA) shows that slab track—which connects track to a concrete slab instead of traditional ties and ballast—prevents sun or heat kink, the buckling of track in hot weather. And in Pueblo, CO, additional PCA-coordinated testing is under way on two 250-ft-long sections of slab track, with initial tests confirming that the system can be constructed to the strict tolerances required by high-speed rail and support heavy axle freight loads. Widely used in Europe and Japan, the system is on track to see increased use in North America.

Tilting up

New technologies in the realm of tilt-up concrete construction are making big dreams come true, according to the Tilt-Up Concrete Association. One of the tallest tilt-up buildings yet is the Pinal County Courthouse in Florence, AZ, with panels taller than 87 ft—making it the second tallest tilt-up structure ever created. At the top of the list is the Seven Rivers Presbyterian Church in Lecanto, FL, with a panel that reaches almost 93 ft high.

Photo courtesy of the Tilt-Up Concrete Association

Spanning success

Developments in high-performance concrete are helping create bridges to last a lifetime. With reduced up-front construction costs and lower maintenance costs over the life of the structures, HPC concrete bridges make financial sense. Integrating recycled byproducts into concrete bridges increases concrete’s resistance to corrosive forces, while saving material from landfills. Precast bridge systems also provide dramatic increases in construction speed, according to the Precast/Prestressed Concrete Institute. Such was the case in San Juan, Puerto Rico, where four overpasses along the Baldority de Castro Avenue were constructed with precast, prestressed HPC components in 36 hours or less, minimizing traffic disruptions.

Everyday innovations

Improvements in concrete are making our world a better place every day. At Melrose Commons II, a precast multi-family housing project is providing affordable homes for families in the Bronx. Pavement research is making safer, quieter highways across the nation. The Solaire—the world’s first green residential high-rise, located in Manhattan’s Battery Park City—is a concrete model of sustainable design and construction. Reclamation technologies using soil-cement are bringing new life to old roads and industrial sites once thought unusable. Every day, thousands of people work to create and innovate—and concrete just keeps getting better.

The Westwood Community Church in Chanhassan, MN, is building a new church and community center with a focus on moderate, open, bright architecture that can provide assembly space for more than 1,400 visitors. The MEVA Imperial steel framed panel system, equipped with alkus plastic compound facing, was used to form the facility’s foundation and remarkable 80-ft altar walls. By expanding the form for each pour with up to 16-ft-high panel extensions, the project stayed on schedule and budget.

Contractors now have an easier option for creating colorful architectural concrete. Offered by L.M. Scofield Company through an alliance with Master Builders, Inc., CHROMIX® Admixtures for Color-Conditioned™ Concrete can now be delivered in liquid form, widening the field of color choices for producers, contractors and architects.

An industry leader since 1915, Scofield manufactures engineered systems that extend the inherent versatility and functionality of concrete and improve its appearance. Scofield Systems transform ordinary concrete into extraordinary, creative, and durable surfaces for hard landscaping, vertical construction, and interior floors.

The delivery system marks a new generation of integral coloring admixtures, packaged with the most advanced and accurate computerized dispensing system in the industry to give architectural concrete unmatched strength and beauty. The system can be used to enhance vertical or horizontal construction projects and manufactured concrete products, providing reliable, streak-free color conditioning and performance characteristics superior to concrete colored by raw pigments.

The longest cable-stayed bridge in North America is under construction in Charleston, SC, and crews are making it possible with a unique approach. The Automatic Climbing System (ACS), a hydraulically operated self-climbing formwork system, is ideal for creating 575-ft-tall main piers for the Arthur Ravenel, Jr. Bridge.

ACS was developed by PERI, the world's largest manufacturer and distributor of formwork and shoring equipment for cast-in-place concrete construction. The system has been used successfully on over 100 projects around the world, including the Petronas Towers in Kuala Lumpur and the Viaduc de Millau in France.

A dramatic improvement over conventional jump formwork in terms of productivity and safety, the ACS units are raised without the use of a crane and connected to the structure at all times during the climbing process. The system can be climbed during all weather conditions and can be safely operated at wind speeds of up to 60 mph.

The United Brotherhood of Carpenters and Joiners of America has a new delivery system for the wide array of educational opportunities offered through its network of 200 regional training centers. At the heart of the program is a new, $25-million, 199,000-sq-ft International Training Center (ITC) located on a 14-acre campus setting 10 minutes from the Las Vegas airport.

The new facility acts as a focal point for training delivery, improving craft skills and housing the organization’s research and development efforts. No other trade organization offers the same innovative, business-relevant training system to carpenters, millwrights, floor coverers, mill cabinet workers, pile drivers and other trades of the Brotherhood.

Courses at the ITC also address leadership enhancement, focusing on the areas of personal communication, active leadership, goal-setting and planning. The training goes to the heart of the organization’s mission to equip men and women to be productive partners with union contractors and project owners, delivering the best value for wages paid.

In Austria’s Kirchham by-pass project, tunnel forming operations are going smoothly, thanks in part to a new hydraulic crawler drive manufactured by Doka. The forming carriage used for the project’s cut-and-cover tunnel was outfitted with the first-ever crawler drive, which brings approximately 5 tons of motive power and is suitable for a wide variety of transportation tasks on hard, flat surfaces.

The new crawler drives can move loads of up to 20 tons each, doing so more gently than transport rollers. The track-links of the crawler drive have a footprint of at least 130 sq cm—more than 20 times the average footprint of transport rollers—resulting in gentler transport and no chipping of the base slab.

Flexibility in movement is another benefit the drives bring to the Kirchham project. Diagonal arrangement of the driven crawler units ensures sideways movement if necessary and integral turntables make direction corrections easy.

A new strengthening product offering from VSL is set to change the landscape of concrete reinforcing materials. Hardwire™ is a steel-reinforced polymer (SRP) composite that is bonded externally to structural elements, allowing end users to incorporate ultra high tensile strength fibers inside or outside almost any material.

“Hardwire™ marks the next generation of composites,” says Brian Gallagher, director of marketing for VSL. “It can be used in the construction, repair and upgrade of buildings, bridges, parking garages and special structures, adding strength and increasing load-bearing capacities significantly.” Ideal for concrete applications, the system’s twisted steel wires can be molded into thermoset, thermoplastics or cementitious resin systems.

The core of the Hardwire™ system is Ultra Tensile steel cords, the same cords manufactured and used by Goodyear Tire and Rubber Company. Resistant to fire and corrosion, the SRP composite is as much as 70% thinner and 25% lighter than fiber-reinforced polymer composites in similar applications.

For easier rebar replacement and lower placing costs, ERICO® Inc. offers the LENTON® Terminator, an oversized half coupler that secures to the end of reinforcing steel and effectively replaces conventional hooked rebar. Based on the Shear Cone Theory, the Terminator reduces congestion and is a proven solution for contractors and design engineers who need a simple, reliable, and economical alternative to hooked rebar anchorage. This mechanical system minimizes embedment length, allows for faster installations, simplifies bar placement, reduces rebar congestion by 60% and provides greater design flexibility.