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Therefore, when concreting at cold temperature cannot be avoided, it is essential to have a minimum curing time at a temperature sufficiently above the freezing point of the concrete pore water, so that the early strength of concrete is high enough to resist the inner tensile stress caused by water freezing. [5]
If the surface of the concrete pour is insulated from the outside temperatures, the heat of hydration will prevent freezing. The American Concrete Institute (ACI) definition of cold weather placement, ACI 306, [128] is: A period when for more than three successive days the average daily air temperature drops below 40 °F (~ 4.5 °C), and
A cement accelerator is an admixture for the use in concrete, mortar, rendering or screeds. The addition of an accelerator speeds the setting time and thus cure time starts earlier. [ 1 ] This allows concrete to be placed in winter with reduced risk of frost damage. [ 2 ]
Air entrainment in concrete is the intentional creation of tiny air bubbles in a batch by adding an air entraining agent during mixing. A form of surfactant (a surface-active substance that in the instance reduces the surface tension between water and solids) it allows bubbles of a desired size to form.
Weather warnings remain in force across the UK as Britons are braced for temperatures to plummet as low as minus 16C. ... has extended its cold weather health alert for all of England until Sunday ...
Polymers in Concrete. CRC Press. pp. 40–42. ISBN 9780849348150. J. Marchand; Michel Pigeon; M. Setzer (1997). Freeze–thaw Durability of Concrete. Proceedings of the International Workshop in the Resistance of Concrete to Scaling Due to Freezing in the Presence of De-icing Salts, Sainte-Foy, Québec, Canada. Taylor & Francis. ISBN 9780419200000
A United Airlines passenger has been charged with reckless behavior and fined $10,000 for reportedly urinating in his seat during a trans-Atlantic flight that had to be diverted to Dublin, Ireland.
Mark Cuban, CEO of Cost Plus Drugs, told BI that AI's impact on a company's workforce will be determined by how well the technology is implemented.