VIDEO TOUR — This is a video showing the use of LCC to accelerate road construction on Highway 35 in the Santa Cruz Mountains.
New Expertise to Boost Public Infrastructure, Private Developer Support Capabilities
November 13, 2017, Anaheim Hills CA – – The California Nevada Cement Association (CNCA) today announced the appointment of Tyler A. Bodnar, PE, as Geotechnical Solutions Engineer as part of its Engineered Cement Applications Program. After nine years with the City of Chico, Calif., Bodnar beings substantial technical expertise relevant to the association’s work with public infrastructure and private development organizations.
“We are thrilled to have Tyler Bodnar joining the CNCA Team. He will be another trusted resource that will help owners, designers and contractors become more comfortable and confident with cement based solutions”, said Tom Tietz, executive director of CNCA.
The CNCA Engineered Cement Applications Program provides support for cement-based solutions including: Soil Cement Revetments and Linings, Cement Deep Soil Mixing, Jet Grouting, Lightweight Cellular Concrete, Pavement Recycling with Full Depth Reclamation, Treated Bases & Subgrades, Roller Compacted Concrete, and Solidification-Stabilization.
CNCA is a non-profit trade association committed to developing sustainable and economical construction solutions for California and Nevada with an emphasis on the use of cement and concrete. Association leaders and technical experts provide design assistance, research, and educational opportunities designed to responsibly transform our built environment and improve the lives of the people throughout the region. In addition to geotechnical solutions, CNCA’s regulatory, legislative, marketing, and education efforts also focus on pavement technologies and buildings. For more information about the CNCA please call (714) 694-0800 or go to www.cncement.org
Case Study: Mayhew Levee Profile (PDF)
Excerpt: The Project
The Mayhew Levee is located along American River in Sacramento, and is in place to protect the neighborhood to the south. The Mayhew Levee Raising and Drain project is designed to improve and increase the capacity of the levee and to replace the Mayhew Drain structure at the west end of this reach of levee.
Case Study: Bear Valley Road Project (PDF)
Excerpt: A Rough History
Bear Valley Road is a heavily traveled road that also borders the City of Hesperia to the south (at the centerline – the south half of the road is in Hesperia), carrying approximately 55,000 vehicles each day, with 30% of them being trucks. Bear Valley Road is a heavily utilized, more direct route for traffic accessing I-15 from SR 18 to the east for areas including Apple Valley, Lucerne Valley, and Johnson Valley.
For many years an asphalt-paved street, Bear Valley Road was repaved with asphalt in 2004 but began to display rutting and deterioration immediately.
Case Study: Oak Street Roundabout Project Profile (PDF)
Excerpt: Building on A Long History of Success
Oak Street Roundabout is a landmark entry feature into downtown Roseville. Located right outside City Hall, this project is a pivotal part of the City’s goal to revitalize the downtown area. Other improvements include water spray features and fire pits in an attempt to increase civic pride and downtown foot traffic. Leading up to this project, the intersection of Washington Boulevard and Oak Street was experiencing three times the traffic accidents compared to similar intersections. The City decided to implement aggressive safety measures.
This is an overview of the more comprehensive paper: CNCA – Historic Pavements – Complete Final Report 2017
Excerpt: Ten of these historic concrete streets are profiled to tell this magnificent story. In-depth documentation compiled by NCE includes sources such as: historical societies, local agency records, period newspapers, and current visual surveys.
Each profile describes the construction and maintenance aspects, but also touches on the important role the street has played in the community!
ONTARIO, CALIF . ( Aug. 18, 2017 ) – It’s not every day that a highway is the reason for a major celebration, but for a section of Interstate 10 (I – 10), between Ontario and San Bernardino, a celebration today marked this freeway’s remarkable 70 year journey…and signaled its vital link to the past, present, and future.
State legislators, leadership of the California Department of Transportation (Caltrans), and construction industry leaders gathered today to commemorate the 70-year anniversary of the concrete pavement freeway, which is both a vital link to business, commerce and personal mobility in the region, and crucial key to the provision of goods and services nationwide.
Dignitaries included The Hon. Jim Frazier, Assembly Member (11th District); The Hon. Eloise Gomez-Reyes, Assembly Member (47th District), The Hon. Marc Steinorth, Assembly Member (40th District); John Bulinski, Caltrans District 8 Director, and Allen Hamblen, President/CEO of CalPortland Company and 2017 Chairman of the Portland Cement Association Board of Directors.
In recognition of this pavement’s longevity, the California Senate and State Assembly recognized the freeway with a formal proclamation, calling attention to the pavement’s longevity and remarkable service.
In addition to carrying some 270,000 vehicles per day, this section of I-10 also carries more trucks with heavier payloads than ever before, the proclamation notes. The proclamation also recognizes the freeway for its “sustainability and resiliency to the forces of nature and man.”
Caltrans District 8 Director, John Bulinski stated, “The 70-year pavement life of these sections of I-10 is the mission that Caltrans will continue to provide a safe, sustainable, integrated and efficient transportation system to enhance California’s economy and livability.”
“Manufacturing and distributing cement and other building materials provides us with the opportunity to see the results of the great potential that exists in the built environment,” Hamblen of CalPortland Company said, adding. “When we apply science, technology, and artistry, and add equal measures of sustainable construction practices, almost anything imagined is possible.
When the original U.S. Route 70-99 was planned in 1945 and built in 1947, Caltrans officials likely never envisioned that it would still be carrying traffic 50 years longer than the 20-years for which it was designed.
“By any standard, 70 years is a remarkable period of time for any pavement to last, but considering that it is 8 inches thick – about 50 to 75 percent thinner than most freeway pavements – and that it carries about 180,000 more vehicles per day than the 90,000 it carried less than 25 years ago, it is an exceptional example of pavement longevity,” said Tom Tietz, Executive Director of the California Nevada Cement Association. Tietz served as master of ceremony of the event.
In addition to the many features and benefits of this section of I-10, the pavement was also the first in the nation to employ a restoration method called “diamond grinding.” Diamond grinding removes surface bumps and other irregularities, restoring the pavement almost to its new condition. First used as part of a restoration and expansion project on this section of freeway in 1967, diamond grinding has become a time-tested, reliable, durable and cost-effective alternative to resurfacing or reconstruction.
The event, held at the Ontario Airport Hotel and Conference Center, was co-hosted by CalPortland, Caltrans Region 8, California Nevada Cement Association, Southwest Concrete Pavement Association, with additional support from the American Concrete Pavement Association and Portland Cement Association.
New FDR Publication: Guide to Full-Depth Reclamation (FDR) with Cement
The Guide provides a concise discussion of all aspects of selecting, designing, and constructing a reclaimed, cement stabilized asphalt base in preparation for a new pavement surface layers.
Produced by the National Concrete Pavement Technology Center (CP Tech Center) at Iowa State University’s Institute for Transportation, with funding from the Portland Cement Association, the Guide is available for free download:
Race to Completion
The long life benefits of concrete pavement are well documented in this Las Vegas Sun article on the Boulder City Bypass.
Ric Maggenti, California Department of Transportation
The environmental benefits aside, greener concrete has been chosen for many of the new east spans of the San Francisco-Oakland Bay Bridge as a practical construction material as well as for durability. In these cases, environmental benefits were not the motivation, but rather the need to meet requirements of design and construction.
There are four distinct construction projects completed or underway, some with multiple contracts, to build the 2.2-mile (3.6-km) long bridge across San Francisco Bay between Oakland and Yerba Buena Island. The new bridge will replace the seismically vulnerable east spans of the 1936 San Francisco-Oakland Bay Bridge.
The new bridge from east to west comprises the Oakland Touchdown, the Skyway, the Self Anchored Suspension (SAS) bridge, and the Yerba Buena Island Transition. The Oakland Touchdown uses low-level, post-tensioned, cast-in-place concrete box girder bridges. The west end of these twin parallel bridges connects to the Skyway. The Skyway, now completed, is a 1.5-mile (2.4-km) long precast segmental structure that used the balanced cantilever construction method. The SAS bridge is the signature structure and connects the Skyway to the Yerba Buena Island shore. The SAS bridge will be a single tower bridge with asymmetrical spans. The Yerba Buena Island Transition structures will be prestressed concrete box girder bridges. They will connect the west end of the SAS to the Yerba Buena Island Tunnel.
Construction began with the Skyway. For durable concrete, California Department of Transportation (Caltrans) has required that 25% of the cementitious material be fly ash in almost all of its structural concrete to mitigate Alkali Silica Reactivity (ASR) since 1997. Thus all the concrete on this massive project required at least 25% fly ash. Higher percentages of fly ash were utilized for the large footings and other mass concrete elements. For the pier concrete, the Contractor, instead of using fly ash, chose to use 50% ground granulated blast-furnace slag, which was the maximum percentage allowed by the 2001 specifications. Bid prices indicated that this can be an economical benefit to the contractor as there was no requirement or even encouragement for its use. Though by today’s rapidly changing standards, the amount of supplementary cementitious materials used was modest in the 450,000 yd3 (344,000 m3) of concrete in the Skyway, the Environmental Protection Agency in 2006 recognized Caltrans as a leader in the construction use of waste products.
The west end of the SAS terminates at a massive pier bent. Here the suspension cables will loop around on saddles and head back toward the east end. The span on the west side nearest San Francisco is shorter then the span east of the tower. This creates an uplift on the west side that is countered by massive concrete anchors as well as the weight of the 8200 yd3 (6300 m3) concrete bent cap. Four columns supporting each end of the bent rest on 63x63x33 ft (19x19x10 m) anchorage blocks. To satisfy the restrictive thermal and corrosion requirements, the concrete contained 674 lb/yd3 (400 kg/m3) of cementitious materials including 40% fly ash. In 2004, this was considered a high percentage for California bridge concrete. Compressive strengths were over 9000 psi (62 MPa) at 90 days.
- Measured compressive strengths of concrete used in pile caps.
The portion of the Oakland Touchdown now under construction is 1080 ft (330 m) long and has seven spans over six piers. Under the piers are mass concrete pedestals, which sit on mass concrete pile caps that make up the footing. The pile caps vary in size having a footprint from 46 ft (14 m) square to 52×72 ft (16×22 m). In a cost savings move, Caltrans proposed a passive thermal control plan using 50% fly ash mixes to replace the contractors active thermal control system, which used internal cooling pipes. These mixes had 337 lb/yd3 (200 kg/m3) of fly ash and 337 lb/yd3 (200 kg/m3) of portland cement. The water to cementitious materials ratio was 0.4, the maximum permitted by the specifications for corrosion control. The strength requirement was 5000 psi (35 MPa) at 90 days for the pedestal and 4350 psi (30 MPa) for the pile cap. The average measured strength for all the pedestals was 4620 psi (31.8 MPa) at 28 days and 5720 psi (39.4 MPa) at 56 days. The graph below shows the 28- and 56-day strengths for the pile caps. The average strengths were 4630 psi (31.9 MPa) and 5630 psi (38.8 MPa), respectively. The lowest strengths occurred on samples stored during a 2- to 3-month period when temperature control of the curing room was malfunctioning. A few samples tested at 7 days had average strengths of about 3000 psi (21 MPa). Concrete from four pedestals had an average 90-day strength of 6230 psi (43.0 MPa). One 180-day test result was 6830 psi (47.1 MPa).
As Caltrans strives toward complying with California’s Assembly Bill 32 to reduce greenhouse gases, the Bay Bridge project is an example showing that this need not be a tradeoff with efficient concrete mixes.
Further Information For further information about the mass concrete used in the San Francisco-Oakland Bay Bridge, please contact the author at firstname.lastname@example.org.