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]
During the curing period, concrete is ideally maintained at controlled temperature and humidity. To ensure full hydration during curing, concrete slabs are often sprayed with "curing compounds" that create a water-retaining film over the concrete. Typical films are made of wax or related hydrophobic compounds.
Concrete has immersed from natural resources into man-made processes; evidence of the use of concrete dates back over 8,000 years ago. Today, many construction companies and concrete manufacturers have cut the use of Portland cement in their mixtures due to its production process emitting significant amounts of greenhouse gases into the atmosphere.
What to do when water pipes freeze. Here are tips from The Red Cross. If you turn on a faucet and only a trickle comes out, suspect a frozen pipe. Likely places for frozen pipes include against ...
When atmospheric carbon dioxide (CO 2), or carbonate ions (HCO − 3, CO 2− 3 dissolved in water) diffuse into concrete from its external surface, they react with calcium hydroxide (portlandite, Ca(OH) 2) and the pH of the concrete pore water progressively decreases from 13.5 – 12.5 to 8.5 (pH of water in equilibrium with calcite).
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 ]
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.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!