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At the same time that reports are cascading through Washington, D.C., describing the nation’s crumbling roads and failing bridges, we could be headed for a funding showdown that could put the brakes on current highway projects. The continuing resolution that funds the nation’s highway bill (SAFETEA-LU) is set to expire again Sept. 30. That highway bill is funded similarly to the Federal Aviation Administration bill that stalled last summer in Congress and shut down the FAA for two weeks, during which time all airport construction projects were halted and thousands of construction workers were furloughed.

While another extension of SAFETEA-LU would be considered routine in normal times, the partisan gridlock in Washington makes any long-term highway funding uncertain. The best that the precast industry could realistically hope for right now is a continuation of the 18.4 cents-per-gallon gas tax, which would fund highway and bridge work at current levels and keep projects going. The proposal by Rep. John Mica (R-Fla.), chair of the House Transportation and Infrastructure Committee, is an austere $230 billion that according to some analysts would have the effect of reducing the transportation budget by 35% over the next six years. To Mica’s credit, he is living within the spending cuts and funding restrictions that are contained within the budget passed by the House last spring. A lean transportation budget is a budget nonetheless, and it provides six years worth of certainty, while lacking any big ideas for real progress in rebuilding our transportation infrastructure. Call it a maintenance budget.

Meanwhile, the Senate has two versions of an infrastructure bank in the works. One version, proposed by John Kerry (D-Mass.) and Kay Bailey Hutchison (R-Texas), would create an independent entity with $10 billion in seed money that would, in theory, leverage hundreds of billions of dollars in private capital for infrastructure projects through loans and loan guarantees. The other proposal, backed by Frank Lautenberg (D-N.J.) and John Rockefeller (D-W.Va.), would house an infrastructure “fund” within the USDOT that would enable the USDOT to fund projects through a grant-making process. Both of these proposals are much more complicated than that, of course, but they’ll be batted back and forth in the Senate this fall. There’s talk of merging the two into a hybrid that would likely run into fierce House opposition – and more delays.

The American Society of Civil Engineers stepped into the debate this summer by publishing a study that describes the economic impact that failing infrastructure has on society every day in the United States. According to the study, deteriorating infrastructure will “cost the American people more than 870,000 jobs and suppress the growth of the country’s gross domestic product by $3.1 trillion by 2020.” Not all of that is transportation infrastructure – municipal stormwater and wastewater systems are included, of course, as well as other vital infrastructure components. For most precasters, however, these are all nuts-and-bolts products that form a critical share of many precast businesses.

If you accept the conclusions of the ASCE study, the choice is pretty clear. Members of Congress – both parties – need to put aside the grandstanding, stay away from the TV cameras, stop the name-calling and sit down together in a room and start working on bold solutions to rebuild our infrastructure and put the construction industry back to work. There are many credible ideas out there, but no silver bullets. What needs to emerge is a comprehensive bill that provides certainty of transportation funding for at least five years, combines traditional gas tax funding with innovative new public-private partnerships to rebuild transportation and water infrastructure and incorporates technology to create efficiencies. We need a top-to-bottom restructuring that makes the best use of every available dollar. Here’s the deal: It can’t be done by either party or the administration, but if all sides can set aside their ideologies for this one issue, perhaps they can do something really big for the country. Our future prosperity depends on it.

Recently, the NPCA Technical Committee wrapped up a revision to the Guide to Implementing SCC to reflect current standards and practices. The original document was written in 2006 to assist precast producers through the process of investigating and implementing self-consolidating concrete (SCC) in their operations. Since then, the use of SCC has spread (excuse the pun).

Ed Mansky with Grace Construction Products and member of the Technical Committee said that DOTs across the country not only are accepting SCC but specifying its use in critical applications such as prestressed bridge girders. Arizona DOT adopted its use earlier this year, and Illinois DOT is expected to include SCC in its specifications this fall. He also added that more and more private specifying agencies are requiring SCC in architectural products to help ensure “bughole-free concrete.”

Jamie Gentoso with Sika Corp. and member of the Technical Committee calls SCC “a mix that is optimized for flow characteristics.” The negative stigma that once existed about how complicated and daunting the process of working with SCC was has gone away. “It must be properly mixed, placed and cured, just as you would with conventional concrete,” she said. She also sees widespread use in the northeast region of the United States, noting that engineers are becoming much more open to the use of SCC.

What is SCC?

SCC is a highly flowable yet stable concrete that can spread readily into place, fill formwork with little to no consolidation and without undergoing significant separation. This type of concrete can be ideal for use in precast given the many advantages, but as with conventional concrete, SCC mixes should be carefully designed to achieve the required performance characteristics, and properly placed and cured.

SCC was developed in Japan in the late 1980s due to a lack of skilled concrete laborers. The goal was to create a new type of concrete that required no vibration or additional energy to place and compact. Lack of an adequate work force, highly congested reinforcement and formwork that was difficult to work around were some of the complications that led to the introduction of SCC. To be classified as an SCC, three primary components must exist:

1.         Flowability – The ability to flow into and completely fill all intended spaces in a form under its own weight and without external energy

2.         Passing ability – The ability to flow through and around reinforcement and openings without the development of aggregate blockage

3.         Stability – The ability for SCC to remain a uniform, homogeneous mix during all phases of transportation and placement

Advantages of SCC

SCC is known for having several advantages. Some of these include:

• Reduced labor and energy to place and consolidate

• Reduced noise from consolidation

• Reduced maintenance of vibrators and forms

• Improved finish with fewer voids

• Decreased re-work on finished product

• Improved safety by eliminating personnel standing on forms to vibrate

• Decreased energy to pour densely reinforced members

What to consider when looking to implement SCC

The process of investigating and implementing SCC into your operation can be broken into three components:

1.  Examine your current materials and equipment. Determine what changes may need to be made or equipment purchased in order to produce quality SCC.

2.  Begin a trial batch and training process. A company should allow enough time for experimentation and factor in a learning curve.

3.  Perform a cost/benefit analysis for your plant and products to determine the overall impact of making a switch.

SCC is believed by many to be the future of the concrete industry. With each passing year, it becomes more affordable and easier to use, while the number of facilities manufacturing with SCC continues to grow.

If you are considering the use of SCC and want to view the updated Guide to Implementing SCC, visit www.precast.org and click on Precast Possibilities to access the Technical Services section

The ASTM C478 standard contains the requirements for the manufacture and purchase requirements of products used for the assembly and construction of circular, vertical precast concrete manholes and structures. The scope of C478 includes structures used in precast sewer, drainage and water works. ASTM C478 is an important standard under the jurisdiction of ASTM C13, the technical committee on concrete pipe, established in 1931.

A bit of history

Committee C13 has been around a long time. The concrete pipe industry actually dates back to the late 1800s, as cited in the “Concrete Pipe Handbook” published by the American Concrete Pipe Association: “The history of concrete pipe standards began virtually with the founding of ASTM in 1898. By 1904, eight technical committees had been organized, and in 1904 six more were formed. One of these, Committee C-4 on Clay and Cement-Concrete Sewer Pipe, was the forerunner of Committee C13.”

The committee meets once a year, with approximately 100 members attending over three days of technical meetings. With a membership of approximately 200, C13 currently has jurisdiction over 55 standards published in the Annual Book of ASTM Standards. C13 has nine technical subcommittees that maintain jurisdiction over these standards.
C13’s subcommittee structure and its portfolio of approved standards and work items under construction are listed in the sidebar “Resources & References” on page 10. These standards play a pre-eminent role in all aspects important to the effective standardization of concrete pipe, including material specifications, test methods and installation practices.

The specific scope of C13 is the formulation and review of specifications, methods of test and definitions for concrete pipe, concrete box sections and concrete manhole sections used for constructing sewers, culverts, and for factory-made compression and self-energizing joints. Development and review of practices and guides cover design, installation, testing, economic evaluation and performance of concrete pipe systems.

ASTM C478 and joint materials

C478 opened up new manufacturing standards for joint materials as gasket material technology evolved. In addition to the O-ring gasket cross section, the profile-wall gasket cross section was developed (see ASTM C433 listed below). The following specifications apply to manhole connectors and joints:

•          C923, “Standard Specification for Resilient Connectors Between Reinforced Concrete Manhole Structures, Pipes, and Laterals”

•          C443, “Standard Specification for Joints for Concrete Pipe and Manholes, Using Rubber Gaskets”

•          C990, “Standard Specification for Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants” (Butyl rubber gaskets are commonly used in the industry)

ASTM C1244 standards for negative pressure tests for manholes

To improve the testing of manhole section gaskets, the discussions in C478 led to the profile wall gasket, a connection with no notch that can be reset in the manhole. It is more forgiving than other gaskets and is becoming more the norm.
While the precast manhole is usually able to withstand additional pressure than that prescribed by ASTM 1244, the gaskets are manufactured to withstand a minimum of only 13 psi according to ASTM C443. Under the jurisdiction of Subcommittee C13.06, C923 specifies the assembly to be subjected to hydrostatic pressure of 13 psi for 10 minutes.

Understanding and supporting ASTM standards

The emergence of the 1972 Clean Water Act established the basic structure for regulating discharges of pollutants into the waters of the United States and regulating quality standards for surface waters. Ensuring the separation of human waste from clean drinking water relies on the durability and reliability of underground piping systems. Compliance with ASTM standards protects the integrity of precast concrete pipe systems and the consumer.

Beyond the critical importance of protecting human health and preventing contagious disease, properly designed and produced manholes ensure the safety of workers who handle precast products, and in the long run guarantee quality precast products that comply with accepted industry practices and prevent unnecessary increases in cost to the consumer.

Precast specifying engineers and precast producers need to be up to date on ASTM standards, because construction material technology, manufacturing and installation practices, testing techniques, and state and federal regulations are continuously evolving. ASTM is at the cutting edge of all of these changes; the balance of the members of its technical committees represents the best practitioners in their respective fields.

As a specific example, consider the skyrocketing cost of steel as it relates to precast concrete reinforcement. The changes made to hoop steel specifications means less steel. Overdesigning reinforcement translates into an unnecessary increase in manhole manufacturing costs, which in turn results in increased costs to consumers. ASTM C478 specifications are minimum requirements for manholes, and engineers can specify additional reinforcement to resist point loading.

“Engineers and producers are well-advised to be familiar with the latest precast manhole specifications for three reasons,” said Frederick Cash Sr., a consulting engineer and chairman of ASTM C478. “ASTM standards address the latest technologies in the marketplace; ASTM committees are made up of a balanced membership that includes input from producers, regulators, engineers and consumers – this balanced input produces a good standard; and finally, compliance with current ASTM standards produces the best product for its purpose and best serves the manufacturer and the public.”

Without a good understanding of the current ASTM standards and the best information available from the contributions of the diverse committee member (producers, suppliers, engineers, federal regulators and consumers), the use of old documents (C478-72) instead of the current C478-09 specification does not serve the product’s purpose and is neither in the best interests of the manufacturer nor the consumer.