Cold weather concreting essential: Monitoring mix temperature

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When placing in cold weather, extra precautions must be taken to ensure concrete sets properly and gains adequate strength. The Transtec Group, Texas-based concrete pavement practitioner, notes how the first few days after placement are the most important because that is when cement hydration reaction proceeds the fastest and concrete gains most of its compressive strength. However, cold conditions slow the hydration process, meaning that concrete placed in low temperatures gains less strength than the same mix in warmer temperatures during the same length of time. If the water in the concrete mix freezes, the hydration process stops completely. Even if it thaws, strength gain may not recover.

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Engineers ground rebar, climbing formwork in tower core ascent

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An 850-ft. mixed-use tower has rapidly climbed into the Seattle skyline on the strength of a unique core wall system with requisite volumes of high performance concrete but no conventional rebar. Topped out in early August, Rainier Square Tower marks the debut of what Seattle engineer Magnusson Klemencic Associates (MKA) dubs the Concrete-Filled Composite Plate Shear Wall (CPSW) system.

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Topcon raises concrete paving bar through Millimeter GPS

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Concrete paving is pretty complex and achieving quality, long-lasting results requires skill, the right equipment, and advanced technology. At its root, pavement is an outdoor floor … a hardscape surface covering that is driven or walked on. One of the major advantages of concrete pavements is they are typically stronger and more durable than other types of surfaces. They also can be grooved to provide a tough, skid-resistant surface. A notable disadvantage is that they typically can be more time-consuming to construct. Thus, concrete contractors have turned to technology for production-enhancing efficiencies and improved results.

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TRB 2019: Reduce portland cement content by optimizing gradation

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Materials are the critical component of durable transportation infrastructure, and as such got strong coverage at the 99th annual Transportation Research Board meeting earlier this year in Washington, D.C. There, some 12,000 delegates audited presentations in over 800 sessions, which addressed many aspects of transportation design, construction and policy, and encompassed infrastructure built with cast-in-place concrete.

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TRB 2019: Nanotechnology boosts performance of cementitious grouts

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Precast concrete products were on the agenda of the 99th annual Transportation Research Board meeting in January in Washington, D.C. Over 12,000 delegates heard presentations in 800-plus sessions addressing multimodal transportation policy and construction practice, including materials and design involving precast/prestressed products. Concrete Products was there and we present this report on new research in precast structures and methods. We will look at TRB 2019 research in cast-in-place concrete later this year. The 100th meeting of TRB will take place January 12-16, 2020. For more information, visit www.trb.org.

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Precast/prestressed pavement, deck panels drive research at TRB

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The annual Transportation Research Board meeting in January is one of the highlights of the pavement and bridge research community. This year’s event drew over 13,000 transportation engineers and specialists from the United States and other countries to Washington, D.C. Delegates could audit 5,000-plus presentations in over 800 sessions addressing topics in transportation construction, including projects based on precast/prestressed concrete structures and methods. Concrete Products was there and this month presents a report on new research findings in precast/prestressed research at TRB 2018. We looked at ready-mixed and cast-in-place concrete previously, see March 2018, pages 54-57. For more information, visit www.trb.org.

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TRB: Albedo change study quantifies role in climate change; PCC overlays perform

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The 97th annual meeting of the Transportation Research Board in January drew 13,000-plus transportation engineers and specialists from across the country, and around the world to Washington, D.C. More than 5,000 presentations in over 800 sessions addressed topics in multimodal transportation, including materials and design involving ready mixed concrete and precast/prestressed products. Concrete Products was there and this month presents a report on new research findings in cast-in-place concrete. We’ll look at precast/prestressed related research from TRB 2018 in an upcoming issue. For more information, visit www.trb.org.

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ABCs of TRB: Accelerated Bridge Construction ideal for precast/prestressed

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Technical papers involving accelerated bridge construction and precast/prestressed concrete products were among the 5,000-plus presentations in more than 800 sessions at the 96th annual meeting of the Transportation Research Board. More than 13,000 transportation engineers and specialists from across the country—and around the world—journeyed to Washington, D.C., earlier this year for TRB 2017, and Concrete Products was among them.

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