EPA revisits SCM in procurement guidelines; honors CalPortland and Cemex

The U.S. Environmental Protection Agency has opened a public comment period through July 6 on the Agency’s current list of 61 items that are or can be made from recovered materials in eight Comprehensive Procurement Guidelines (CPG) categories, plus recommendations to federal agencies on purchasing such items. The largest category, Construction Products, includes blended cement or concrete containing fly ash, ground granulated blast furnace slag and silica fume.

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Alternative SCM, industrial mineral blend catapults C-S-H formation

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California-based construction materials specialist Surface Tech is commercializing an alternative supplementary cementitious material (ASCM) whose requisite chemical profile (silicon dioxide + aluminum oxide + iron oxide content > 75 percent) belies binder-optimizing performance potential exceeding that of leading SCM. While fly ash, GGBF slag and silica fume tend toward dosages starting at 10 percent by weight of portland cement, Juno XP has exhibited marked strength development characteristics at 2.5 percent and 5 percent when measured against portland cement controls—particularly at seven- and 28-day cylinder breaks.

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FHWA assesses SCM, natural pozzolans within best pavement practices

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A new Federal Highway Administration Tech Brief cites benefits and drawbacks of fly ash, slag cement, silica fume and natural or alternative pozzolans for transportation structure-grade concrete. “Supplementary Cementitious Materials — Best Practices for Concrete Pavements” (FHWA-HIF-16-001) outlines how agencies overseeing road construction and maintenance confront increasing service demands on concrete structures, expectations for reduced environmental impact, plus lower initial and lifecycle costs.

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FHWA probes SCM, natural pozzolans within best pavement practices

Sources: Federal Highway Administration; CP staff

A new FHWA Tech Brief cites benefits and drawbacks of fly ash, slag cement, silica fume and natural or alternative pozzolans for highway-grade concrete. “Supplementary Cementitious Materials — Best Practices for Concrete Pavements” (FHWA-HIF-16-001) outlines how transportation agencies approach increasing service demands on concrete structures, along with expectations for reduced environmental impact plus lower initial and lifecycle costs.

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Australians test carbon dioxide-capturing carbonate production

Sources: University of Newcastle; CP staff

A new method for permanently storing carbon dioxide emissions generated from fossil fuels and other industrial processes is at the heart of a mineral carbonation pilot plant to be built at the University of Newcastle’s Institute for Energy and Resources.

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Coal operator Alpha takes stake in Class C ash-based cement purveyor Ceratech

Sources: Alpha Natural Resources, Abingdon, Va.; CP staff

A major coal producer has acquired a 10.3 percent position in Alexandria, Va.-based Ceratech Inc., whose Ekkomaxx technology can yield concrete binding agents with performance characteristics reportedly matching ASTM C150 Types I–V powder.

Alpha Natural Resources can increase its Ceratech stake to 28.3 percent under certain future terms. It becomes the second coal producer to invest in prospective concrete technology offsetting carbon dioxide emissions from either portland cement production or fossil fuel-fired power generation. In April 2010, market leader Peabody Energy took a $15 million interest in Calera Corp., whose calcium carbonate precipitation processes—applied to power plants’ flue gas streams—are netting concrete-grade fine aggregate.

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SCM, aggregate processor Calera eyes concrete pilots for CO2-sequestering carbonate

Sources: CP staff; Calera Corp., Los Gatos, Calif.

Two years after outlining research aimed at commercial processes for carbon dioxide-capturing aggregate or cementitious materials, Calera has announced a series of prospective concrete applications testing a mix agent from its Mineralization via Aqueous Precipitation technology. An initial carbonate product, Partial Cement Substitute (PCS), is derived from the flue gas of the Moss power plant in northern California, coupled with naturally occurring, water-based calcium or magnesium sources.

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CO2-Capturing Aggregate Processor Calera Lands $19.8 Million DOE Grant

Los Gatos, Calif.-based Calera Corp. is poised to design, build and operate a system that mineralizes carbon dioxide from flue gas, yielding carbonate-bearing aggregate for construction fill or cement mill raw feed

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