Search results
Results from the WOW.Com Content Network
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]
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] Concrete is damaged if it does not reach a strength of 500 pounds per square inch (3.4 MPa) before freezing. [3]: 19
Accelerated curing is any method by which high early age strength is achieved in concrete. These techniques are especially useful in the prefabrication industry, wherein high early age strength enables the removal of the formwork within 24 hours, thereby reducing the cycle time, resulting in cost-saving benefits. [ 1 ]
Science & Tech. Shopping
How fast does a 50-gallon rain barrel fill up? How fast a 50-gallon rain barrel fills up depends on the intensity and duration of rainfall and the size of the catchment area (such as the roof).
Once applied, the concrete must cure in a moist environment two to three hours after the application. This is achieved by spraying the surface with water at least three times a day for a few days. Evaporation retardants are also occasionally used. Depending on the climate, the curing process may take longer and require more frequent wetting.
In arid climates, rain barrels are often used to store water during the rainy season for use during dryer periods. Rainwater tanks may have a high (perceived) initial cost. However, many homes use small scale rain barrels to harvest minute quantities of water for landscaping/gardening applications rather than as a potable water surrogate.
A pervious concrete street in 2005. Pervious concrete (also called porous concrete, permeable concrete, no fines concrete and porous pavement) is a special type of concrete with a high porosity used for concrete flatwork applications that allows water from precipitation and other sources to pass directly through, thereby reducing the runoff from a site and allowing groundwater recharge.