ASTM Proposed Standard: Recycling of Returned Ready-Mixed Concrete

A proposed new ASTM International standard will cover the process, verification and record keeping procedures for recycling returned fresh concrete. The proposed standard, ASTM WK39876, Specification for Returned Fresh Concrete for Use in a New Batch of Ready-Mixed Concrete, is being developed by Subcommittee C09.40 on Ready-Mixed Concrete, part of ASTM International Committee C09 on Concrete and Concrete Aggregates.
 
A significant amount of concrete is returned to manufacturing plants, which can result in wasted material, the need for disposal and unnecessary environmental impact. These issues can, however, be minimized since some of the returned concrete is suitable for reuse and can be incorporated into new batches. A proposed ASTM International standard will ensure that returned fresh concrete mixed with new concrete has known and verifiable characteristics.

“Concrete is the most widely used building material in the world,” says Eric Koehler, VP, Verifi LLC, and chairman of the task group developing ASTM WK39876. “The proposed standard will help ready mixed concrete manufacturers reduce waste material and disposal requirements. Purchasers and specifiers of concrete can obtain concrete with greater recycled content while ensuring the concrete is of high quality.”

Koehler notes that technology available to facilitate the reuse of returned fresh concrete includes hydration stabilizing admixtures that can be used to extend the setting time of concrete and ensure that concrete can be used in a new batch. In addition, truck-mounted equipment can be used to measure, manage and record concrete slump, water content, temperature and load size throughout the delivery cycle to reduce the need for manual testing.

Subcommittee C09.40 welcomes all interested parties, particularly those with experience in using returned fresh concrete, to contribute to the ongoing development of ASTM WK39876.

ASTM International welcomes participation in the development of its standards. For more information on becoming an ASTM member, visit www.astm.org/JOIN.

Check Out This Sustainable Insulation Product...Made From Blue Jeans

What will they think of next? UltraTouch Denim Insulation is a green and sustainable insulation that is sourced entirely of post-consumer blue jeans. Manufactured by Bonded Logic Inc., the insulation gives denim another life cycle by transforming it into cotton batt insulation. This diverts waste material from landfills - about 300 tons monthly. Recycled denim is comprised of cotton fibers, a rapidly renewable resource with a rapid growth cycle.



UltraTouch Denim Insulation is free of harsh chemicals and treated with a borate-based solution for fire retardancy and mold/mildew growth. That means the product contains no added formaldehyde. Borat is an EPA-registered material that has a lower toxicity than average table salt. The insulation has been tested and shows no volatile organic compounds (VOC) within the product or off-gassing concerns.

UltraTouch Denim Insulation offers maximum thermal performance and has a 30 percent to 50 percent increase in acoustical performance over traditional insulation for high sound proofing. In addition, groups can earn up to 12 LEED credits by using UltraTouch Denim Insulation.

Installation

The insulation comes in batts (rectangular strips), so no specialized equipment is needed to install it. A portion of the batts in each package contains several perforations, allowing consumers to easily size the batt to the dimensions needed. Similar to perforations on a paper towel, perforated batts allow you to tear the insulation with your hands.

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Manufacturing process

The sustainability of UltraTouch Denim Insulation continues with the manufacturing process, which uses minimal amounts of energy in comparison to traditional insulating products. All scrap and manufacturing trim is re-introduced into the raw material supply creating a virtually zero waste process.

Flawed EPA Coal Ash Analysis

Two years after the Kingston, Tenn., coal ash spill, federal action to regulate coal ash dumps is being held up by concerns that stricter standards would depress markets for coal-ash recycling. Cost-benefit analysis estimates prepared by the U.S. Environmental Protection Agency (EPA) claim that coal ash recycling is worth more than $23 billion a year, based on the annual life-cycle benefits of avoiding pollution and reducing energy costs. But there’s just one problem: That estimate is more than 20 times higher than the $1.15 billion that the U.S. government’s own data shows is the correct bottom-line number, according to a review conducted by the independent and nonprofit Environmental Integrity Project (EIP), Earthjustice, and the Stockholm Environment Institute’s U.S. Center (based at Tufts University).

The flaws in the EPA cost-benefit analysis appear to have escaped scrutiny at the White House Office of Management and Budget (OMB), which required EPA to include a weaker coal-ash proposal favored by utilities and some coal ash recyclers. Common sense and past experience indicate that stricter standards for disposal will work to increase, rather than decrease, recycling. But either way, EPA ought not to be intimidated into adopting weak rules based on grossly inflated values for coal ash recycling, the three groups said.

Presented recently by Environmental Integrity Project, Earthjustice, and the Stockholm Environment Institute, the new EIP analysis (www.environmentalintegrity.org) shows that the huge discrepancy is due to several factors, including double counting of pollution reductions that the EPA has already claimed would occur separately under Clean Air Act rules adopted in August 2010, overstated emission levels from cement kilns, and unrealistic assumptions about potential energy savings from reducing energy consumption at cement kilns and gypsum plants.

For example:

* About half of the coal-ash recycling benefits claimed by EPA are based on assumptions that substituting fly ash for 15 percent of U.S. cement production would cut fine particle emissions by more than 26,000 metric tons per year. But the EPA’s Office of Air and Radiation has estimated that the entire cement kiln industry releases just over 15,000 metric tons per year, and projected emissions already would decline to about 3,500 metric tons by 2013 when separate Clean Air Act standards for that industry take effect.

* EPA estimated that recycling fly ash in cement kilns saves $4.9 billion in energy costs in the analysis prepared for the coal ash rule. But the Agency’s Office of Radiation, in analysis developed to support the separate and more far-reaching Clean Air Act standards, estimated total energy costs for the entire industry at no more than $1.7 billion.

EPA’s cost-benefit analysis also neglects to account for many of the quantifiable benefits that would result from stricter standards, and puts an enormous dollar value on the so-called stigma” that would supposedly attach to coal ash recycling by virtue of regulating disposal sites. These economic assumptions are haphazard, unsupported by the record, and designed to slant the playing field against regulations that are based on protecting the public’s health.

Environmental Integrity Project Director Eric Schaeffer said, “Unfortunately, EPA and OMB just got this wrong. The regulatory impact analysis prepared by EPA to support its proposal exaggerates the economic life cycle value of coal ash recycling, which could end up stacking the deck in favor of the weaker regulatory option favored by industry. Somehow, the agency has let itself be distracted by bogus economic arguments, instead of determining how best to protect the public from leaking ash dumps. In any case, coal ash recycling would not stop under the stronger of the two rules at the EPA. Coal combustion waste can be recycled responsibly, help reduce disposal costs and, in some cases, reduce energy or raw materials cost when coal ash is used as a substitute. All evidence suggests that strict regulation of coal ash disposal sites will encourage recycling, as industries seek to avoid the higher disposal costs.”

Frank Ackerman, senior economist, Stockholm Environment Institute, said, “We found numerous errors, large and small, in EPA’s cost-benefit analysis of the proposed rules. Once we corrected those errors, the strict regulatory option is the clear winner. The only argument for the weaker option is industry’s unsubstantiated claim that strict regulation of ash disposal would cause immense, long-lasting harm to the market for ash recycling. In reality, strict regulation of disposal would make recycling more attractive, not less.”

Abigail Dillen, staff attorney, Earthjustice, said, “It should come as no surprise that requiring safe landfills for coal ash is less costly than allowing ash dumps to contaminate water in hundreds of communities around the country. What is surprising, in the face of this major public health threat, is that the books are being cooked to accommodate the coal industry.””

The groups emphasized the following:

* About $400 million has been spent so far to clean up the TVA Kingston spill with more than 3 million tons of spilled ash removed from the site. However, the cleanup is far from complete. Meanwhile, at least 50 similar, unregulated high-hazard dams around the country continue to pose a similar risk of catastrophic failure, and many more ash dumps are currently contaminating groundwater. EPA, EIP, and Earthjustice have documented over 100 dump sites where coal ash has poisoned water supplies.

* EPA’s own risk assessments reveal that arsenic levels in drinking water around unlined ash ponds can be high enough to cause cancer in one of 50 people, which is 2,000 times EPA’s acceptable risk level. Yet, there is evidence that this high cancer risk is substantially underestimated. The leading arsenic experts in the country observe that this risk is actually 17.5 times greater.

* A review of state regulations shows that the majority of states fail to require essential safeguards for coal ash landfills and ponds, including liners, groundwater monitoring, leachate collection, dust controls and financial assurance. In the two years since the disaster in Kingston, little has been done to improve state controls. Only four states in the U.S. require all landfills to be monitored and only six states require all ponds to be monitored for leaks.

For more information, visit www.environmentalintegrity.org.