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I n early September of 2019, Gulf Coast Underground (GCU) received a call from the City of Baton Rouge and their construction manager, Jacobs Engineering Group (JEG). There was an issue at the South Wastewater Treatment Plant that would require a unique contractor skillset to properly repair. The problem was that the cast-in-place influent structures receiving 65 million gallons (246 ML) of sewer flow daily, were corroding and needed to be repaired quickly

If asked, could you accurately explain why the choice of slump is so important to a wet-mix shotcrete material’s hardened properties?

The Park Avenue Tunnel, formerly known as the Murray Hill Tunnel, is a 1,393-foot-long (425 m), 16-foot-wide (5 m), 9-foot-tall (3 m) thoroughfare traversing six New York City blocks. The tunnel was originally constructed in 1837 as an open rock-cut, with a brick arch constructed over the cut in 1854 to create the tunnel profile. For the next 150 years, the tunnel would be plagued with issues ranging from mechanical system failures to liner wall leakage due to the soil volume above, which is where the idea of shotcrete stabilization was introduced within the project scope.

People have been traveling to the small Caribbean island of Barbados to surf the ever-present waves arriving across the Atlantic for as long as humans have pursued wave riding. The same can be said about skateboarding as the parish of Christ Church now boasts a regional concrete skatepark! This was a long and thorough process shepherded by a consortium of firms and associations, all working to provide the Bajans a modern concrete skatepark through proper planning and processes. This all began with one phone call from Paul Wilson, a local skateboarding advocate with the tireless passion to bring proper skateboarding to the youth (of all ages) of Barbados.

The ASA President’s Award was established in 2005 to recognize a person or organization that has made exceptional contributions to the shotcrete industry. It is the sole responsibility of the immediate outgoing President of ASA to select the recipient of this award. Since 2006, 14 well-deserving individuals and one organization have been awarded the ASA President’s Award, all of whom dedicated their time and energy to advancing the shotcrete industry. For 2020, at the virtual Sixteenth Annual ASA Awards Celebration, the immediate outgoing President of ASA, Ryan Poole, presented this award to Lars Balck, for his exemplary leadership in the shotcrete industry, advancing and facilitating the mission of ASA.

When you are faced with a project with limited access, material delivery by helicopter, the nearest personnel access is 5 miles (8 km) away, and the closest outside access to the shotcrete placement location is a half mile away, the only solution to handle all of these issues is shotcrete. The Poe Tunnel is a 15 mile (24 km) long tunnel in the foothills of the Sierra Nevada Mountains and is in an area of steep canyons. The tunnel transports water from a forebay on the North Fork of the American River to the Poe Powerhouse where electrical power is generated. The tunnel is almost 20 ft (6 m) in diameter and was constructed in the 1950’s.

Shotcrete was essential to create the smooth flowing transitions, curves, and blends required in the construction of the Hale Park Skatepark in Wenatchee, WA. All of our skateparks, including Hale Park, are constructed of steel reinforced shotcrete with a minimum 28-day compressive strength of 4000 lb/in2 (28 MPa) – often breaking over 5000 lb/in2 (34 MPa) in just 7 days. Using proprietary techniques and products, developed over the years, we can form and sculpt shotcrete into virtually any shape imaginable. This gives us the ability to produce any skate feature requested or imagined by the project stakeholders.

When one of our core builders called us to announce their prospective client’s desire to completely redo their beach house on the Sound in Corolla, NC, they mentioned that a new concrete pool would be part of the project. Steve Daniels, of Renaissance Construction Company, Inc., had his designer, Paul Gilbertson, send us preliminary information on the prospective property and the client’s wish list for the backyard. To call it a transformation is a significant understatement

Florent Pastorelli is currently completing his master’s degree in mechanical engineering at Université Laval in Québec City, QC,Canada. Originally from France, where he trained as a mechanical engineer at the Arts & Métiers school, Florent decided to pursue his education in Québec City in the field of robotic engineering. His research project focuses on the automation and optimization of shotcrete placement by the use of a computer controlled robotic arm. This project is part of a larger project developed by Marc Jolin’s Shotcrete Research Team, the SPARO project (Shotcrete Placement Automated by Robot)

located in El Paso, TX, the El Paso Zoo sits on 35 acres (1400 m2 ) of land and houses over 220 animal species from around the world. Accredited by the Association of Zoos & Aquariums (AZA), the El Paso Zoo’s mission is to celebrate the value of animals and natural resources and create opportunities for people to rediscover their connection to nature. Locally recognized as the “Best Place to Take Your Kiddos,” the El Paso Zoo features family favorite attractions like African Star Train, Foster Tree House Playground, and now home to the award winning Chihuahuan Desert exhibit.

Bald Head Island, off the southern shores of North Carolina is a 6 mi2 (16 km2) island, accessed only by ferry, for guests, and by barge, for construction. It is steeped in history, playing a part in both the American Revolution and the Civil War. Feared by seamen, it is well protected by 30 mi (48 km) of shoals right off the cape into the Atlantic Ocean, known as the Frying Pan Shoals. North Carolina is famous for its barrier islands that

The 15th annual Carl E. Akeley Award was presented to Antoine Gagnon, Marc Jolin, and Jean-Daniel Lemay from Université Laval, for their article, “Performance of Synthetic Sheet Waterproofing Membranes Sprayed with Steel Fiber-Reinforced Shotcrete Testing for Waterproofing Membrane Integrity After Spraying,” published in Shotcrete magazine, Fall issue of 2019. This article is aimed at evaluating the potential damage and performance reduction of synthetic sheet waterproofing membrane when using steel fiber-reinforced shotcrete.

In 2015, the U.S. Army Corps of Engineering began construction on the Davis Barracks at West Point, NY. The 172 million dollar barracks became a state-of-the-art facility. The new barracks was built to house 650 cadets, three in each room, consisting of 297,392 ft2 (27,629 m2).
The barracks building is located on the side of a mountain, below the cadet chapel, which in of itself is a famous landmark. The site for the barracks posed numerous challenges which included the removal of 285,000 tons (259,000 metric tons) of granite for the building’s foundation. Between 2015 and 2017, during the construction, over

Recruiting, training, and retaining skilled shotcrete nozzlemen is mission-critical for a company’s success. Virtual, immersive training offers an effective, engaging mode of learning that supports the modern trainee. For beginning nozzlemen, virtual reality training gives them a safe, repeatable experience that can be completed in a classroom, free of job costs. Practice without cost or risk also helps improve job performance and satisfaction. These disruptive virtual reality (VR) technologies can provide safe, hands-on learning experiences without the field costs associated with hands-on training. Virtual learning is also valuable in today’s socially distanced world with its shifting remote learning requirements. Interactive digital tools will deliver meaningful, adaptive training for skilled trades now and in the future. Though some level of hand nozzling experience is still needed the best nozzlemen will be trained, in part, using virtual reality.

Using shotcrete for the placement of concrete for tunnel final linings is becoming more common. In the past the use of shotcrete final linings was typically limited to non-public or emergency egress areas, however, shotcrete is being used more and more in public areas. The use of shotcrete is typically an attractive alternative to form-and-pour final lining installation where formwork costs are high or technically challenging, pose a scheduling issue, or where labor rates are very high. Typical examples for successful use of shotcrete final linings are complex lining geometries, intersecting or merging tunnels, widenings, short tunnels without sufficient repeating utilization of the forms, or underground systems where formwork would block passing traffic.

The manual hand application of shotcrete began over 100 years ago and continues today in a wide range of applications and projects. To provide a proper distance of the shotcrete nozzle tip to the underground surface wall, surface receiving shotcrete or ‘substrate,’ the hand application of shotcrete in larger diameter underground structures required the nozzlemen to operate from a man-lift or similar equipment. Working from elevated platforms and the close proximity of the nozzleman to the substrate added safety challenges to projects. Thus, as more underground projects started to use the wetmix shotcrete process, spraying shotcrete with mechanical arms began to address these safety concerns.

Although many shotcrete workers “claim” to be capable of placing massive amounts of concrete in a daily shift, or shooting with the pump turned “wide open,” in reality, the nozzleman tends to ultimately be the limiting factor on production speed and daily placement volume. Plain and simple they get tired. Shooting too fast diminishes accuracy and overall quality.

We have all seen those small letters and numbers that mark practically everything we use in construction. To most, these are meaningless markings that are meant for someone else. However, with shotcrete, nothing could be farther from the truth.

The COVID-19 Pandemic affected our lives in ways none of us have ever experienced in our lifetimes. I’ve been in construction for 45 years and I have never seen our economy shut down, businesses closed, or people required to stay at home. In 2001, the attacks of September 11th temporarily shut down air travel and the stock market, but the American economy remained intact and air travel resumed within a couple of weeks. However, COVID-19, has affected our lives in ways that we could never have imagined. Schools and universities were closed; professional, collegiate and high school sports seasons were suspended and canceled; and restaurants and businesses were closed. We were told to stay home and work remotely, if possible, and businesses across the country followed those directives.

Show me a person who tells you that safety on a mine site is just plain common sense, and I’ll show you someone who doesn’t understand mine safety completely. Mine safety is not simply common sense. It is that, and a whole lot more. Most mines have their own set of mine-specific regulations and rules. Nearly all mines, in Canada, the USA, and Mexico, are required by law, to follow government-mandated requirements such as U.S. Department of Labor- Mining Health & Safety Administration (MSHA) and/or the Occupational Safety & Health Administration (OSHA). Canada and Mexico have their government agencies governing mining as well. Even with strict government regulations, most mines have safety regulations specific to each individual mine. Anyone who desires to visit a mine site needs to accept one thing- whatever the rules and regulations are for a particular mine- these regulations are serious business and are meant to be enforced.