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The mono-sulfate (AFm) now more soluble at low temperature slowly dissolves to recrystallize as the less soluble ettringite (AFt). AFt crystal structure hosts more water molecules than AFm. So, AFt has a higher molar volume than AFm because of its 32 H 2 O molecules. During months, or years, after young concrete cooling, AFt crystallizes very ...
The second consideration is the high thermal mass of concrete slabs, which applies similarly to walls and floors, or wherever concrete is used within the thermal envelope. Concrete has a relatively high thermal mass, meaning that it takes a long time to respond to changes in ambient temperature. [9]
The ultimate strength of concrete is influenced by the water-cementitious ratio (w/cm), the design constituents, and the mixing, placement and curing methods employed.All things being equal, concrete with a lower water-cement (cementitious) ratio makes a stronger concrete than that with a higher ratio. [2]
The same study found that air temperature rise in summer is higher than in winter and it also depends on the climate. [16] The ground floor with a slab on grade has less temperature rise compared to middle and top floors, and an increase of the supply air temperature causes a decrease in the temperature rise.
Conversely, cool air falls to the floor as it is heavier than the surrounding warmer air. [citation needed] In a stratified building, temperature differentials of up to 1.5°C per vertical foot is common, and the higher a building's ceiling, the more extreme this temperature differential can be. [2]
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Hawaii is the only state to not record a subzero temperature: The coldest temperature recorded in Hawaii is 12 degrees at the Mauna Kea Observatory, at an elevation of 13,796 feet, on May 17, 1979.
Over the past 100 years, the average July temperature in Phoenix has risen dramatically. In the 1920s, it ranged from 89.3 to 92.7 degrees; in the past decade, it sat between 94.7 and 102.7 degrees.