Vote for the name of TXI’s internal curing process using rotary-kiln lightweight aggregate

TXI’s rotary-kiln lightweight aggregate has revolutionized the ability to design and build stronger, longer-lasting, greener structures ranging from highways to high-rise buildings.

Last month we asked for ideas and we received over a hundred great ones.  We’ve narrowed it down to a few finalists.  Now, we would like your vote for the final name. Vote now

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TXI lightweight aggregate enhances the concrete curing process from the inside out (internal curing) to provide greatly increased service life, reduction or elimination of drying and plastic shrinkage cracking of concrete, abatement of alkali-silica reactivity and the potential for LEED credits toward innovative design.

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Green Considerations: Focus on Concrete

Concrete is a strong, durable material with high heat storage capacity that can be used to moderate building temperature swings. Because traditional concrete is one of the most inert building materials, it is generally also a good product from an indoor air quality standpoint, even for chemically sensitive people.

Concrete does, however, have some environmental drawbacks. It can cause water pollution if wash-out water from equipment at concrete plants or on job sites finds its way to local waterways. The pH of washout water is so high, it is toxic to aquatic life. Another concern is the production of cement, the binding agent used in concrete, which accounts for about 10%–15% of concrete’s mass, but 92% percent of its embodied energy.

Cement manufacture is a major contributor to atmospheric greenhouse gases due to both its production and process emissions. Cement production accounts for 1.5% of all U.S. CO2 emissions (according to the Portland Cement Association); worldwide, however, cement production causes over 8% of the total CO2 emissions attributed to human activity. To its credit, the cement industry has made great strides in recent decades to increase energy efficiency and reduce emissions.

Furthermore, ongoing developments in concrete production can reduce environmental impacts by substituting other materials for cement. Up to 60% of the cement content used in traditional concrete may be replaceable with a “supplementary cementitious material” (SCM) salvaged from industrial waste (or derived from natural soil or rock), depending on the concrete application, the type and quality of the substitute, and the results of batch testing.

Industrial by-product SCMs include fly ash, a waste product from coal-fired power plants, blast furnace slag, a waste product from steel production, silica fume, a waste product from the silicon metal industry, and rice hull (or husk) ash, which is generated when agricultural rice waste is burned to produce power. Replacing a percentage of the cement in concrete with an SCM reduces energy consumption and CO2 production, reduces solid waste, and can improve concrete strength, performance, and durability.

To minimize the environmental problems with concrete, the following measures should be taken.

• Reduce concrete waste by recycling crushed concrete for fill material or road base, or grinding it up for aggregate. (Currently only 5% of concrete is recycled. By weight, it represents up to 67% of construction and demolition waste.)
• Carefully estimate the amount of concrete required to avoid ordering excess amounts that become waste.
• Consider less material-intensive alternatives to poured-in-place concrete, such as insulation-form walls and autoclaved cellular concrete block. Precast concrete is factory-made to order, which, due to controlled production processes, also reduces concrete waste.
• Use insulated shallow foundations in northern climates; consider pier-and-beam foundations instead of slabs on grade.
• Protect aquatic ecosystems by washing forms and equipment where runoff will not contaminate waterways.
• Use the maximum amount of fly ash or other SCM appropriate to the construction application, location and material quality.

Excerpted with permission from Green Building: Project Planning & Cost Estimating, 2nd Edition, published by RSMeans.