0
Want this question answered?
Be notified when an answer is posted
Add your answer:
Earn +20 pts
How long should you wait before you seal concrete?
AnswerTypical concrete takes 28 days (4 weeks) to cure. Prior to the 28 days concrete still has moisture in it that weakens the strength of the concrete. If you seal it prior to 28 days there is a chance you will be sealing in some of that moisture and hence weakening the integrity of the concrete. Another more common problem that occurs when you seal in the moisture is you can see white cloudy bloches which is really the reaction of the moisture and sealer. This prevents a strong bond for the sealer and the sealer can peal up. Ok, all that said, the 28 days really is condition dependant. If you poured your concrete in the middle of dry summer then 14 days should be the minimum amount of time you should wait. After you seal the concrete (depends on conditions and sealer product) you will typically want to give the sealer 1 day prior to walking on it and 48 hours after application before driving on it. Again depends on type of sealer (ie. epoxy...). concretenetwork.com has a lot of good info as well. Good luck.
How many days concrete has to be cured prior to steel erection What counts days or strength achieved by concrete?
the strength that it has gained is the main thing, but usually 5 to 7 days as a rough guide.
What is the difference between cement and concrete?
Concrete is made from cement. Concrete has cement, rock and sand mixed with water. Cement is just the powdered hydrated limestone.Cement is a building material that is a powder made of a mixture of calcined limestone ( calcined: to Heat a substance so that it oxidizes or reduces) and clay; when cement is used with water and sand or gravel it makes what is referred to as concrete or mortar.Reinforced concrete means that there is a mat of rebar (iron rods) metal, and/or mesh added to provide extra support against stresses and is laid out prior to the pour of concrete.Grout is a thin mortar that can be poured and used to fill cracks in masonry, ceramic tile or brickwork.regular curingIt is critical to concrete's long-term durability that it be kept as moist as possible for the first seven days after placement. In addition, it must be allowed sufficient drying time before being subjected to freezing temperatures or to de-icing salts. Curing concrete properly requires the correct control of moisture and temperature and without proper curing, concrete may only achieve 50% of its potential design strength. The logic behind the practice of a seven day curing period rests on two facts:Cement, the "active" ingredient in concrete requires constant moisture to gain strength.If the concrete is kept moist for the seven day period, it will not only gain strength, but will also shrink less and produce fewer cracks.Curing can be assisted in a number of ways:Spray-on liquid curing agents and sealers.Water ponding or spraying a mist over the concrete.Coverings such as wet burlap, polyethylene, insulating blankets, etc.Leave forms in place.A liquid curing agent is the most effective and convenient method. The curing agent should be applied as soon as finishing is complete. Curing agents form a membrane on the surface of the concrete in order to retain moisture. Once the curing agent has been applied, no further working of the concrete can be done. Use a spray or roller to apply curing agents.According to CSA A23.1-94, curing is a mandatory part of concrete construction and requires moisture to maintain the concrete at 100% relative humidity and a minimum temperature of 10°C for a period of at least 3 days. This period is extended to a minimum of 7 days for the durability requirements of exposure classes F1, C1, C2, S1, and S2.cold curingConcrete can be placed safely throughout the colder months if precautions are taken. During colder weather, the mix should be adapted to the ambient temperature by heating the concrete, adding accelerators, and providing protection. during colder condition's, it is important to heat all concrete to meet the requirements of CSA and to maintain reasonable setting times and strength gain.Concrete generates heat during the hydration process, (the chemical process by which cement reacts with water to form a hard stable paste). Hydration is affected by initial concrete temperature, ambient air temperature, the dimensions of the concrete and mix design.The temperature of the concrete during and after placement is critical since concrete sets more slowly as the temperature drops. Finishing and form removal may be delayed in cool weather and strength development can be impaired if appropriate precautions are not taken.whenever possible , if not always, do not place concrete on frozen ground, on snow, or in freezing weather. If concrete freezes while in a saturated condition, surface problems like scaling, spalling or cracking can arise due to the expansion and contraction of frozen water inside the concrete.During freezing weather, water curing of concrete should be terminated 12 hours before the end of the protection period.Do not use a curing agent if there is any chance that the concrete will freeze during the curing period.Protect concrete from freezing temperatures for 3 to 7 days after placing.Leave forms in place as long as possible. Corners and edges are most vulnerable (cover and heat if necessary).Protect flatwork by covering and heating, or using insulated blankets, or covering with plastic and straw.This information has been provided to assist you .For a complete review of cold weather concrete practices, please refer to CSA A23.1 -- 94 Section 21.
How do you waterproof a slab on grade foundation?
Use polyethylene sheet membrane. Prior to concrete placing, cover the entire area with a layer of PE sheet membrane extending the perimeter of slab and up against wall for the depth of concrete.
What is the advantages and disadvantages of pretensioning method of concrete?
pretensioning is the process of inducing reverse stresses to concrete prior to design loading so as to achieve slender sectins thereby reducing cost. disadvantages of pretensioning are losses due to slip, etc
Can frozen bread make you sick?
If it became contaminated prior to freezing or wasn't properly packaged and became contaminated in the freezer, it could cause illness. By itself, the actual freezing of bread should not create a situation that would cause someone to get sick.
How long should you wait before you seal concrete?
AnswerTypical concrete takes 28 days (4 weeks) to cure. Prior to the 28 days concrete still has moisture in it that weakens the strength of the concrete. If you seal it prior to 28 days there is a chance you will be sealing in some of that moisture and hence weakening the integrity of the concrete. Another more common problem that occurs when you seal in the moisture is you can see white cloudy bloches which is really the reaction of the moisture and sealer. This prevents a strong bond for the sealer and the sealer can peal up. Ok, all that said, the 28 days really is condition dependant. If you poured your concrete in the middle of dry summer then 14 days should be the minimum amount of time you should wait. After you seal the concrete (depends on conditions and sealer product) you will typically want to give the sealer 1 day prior to walking on it and 48 hours after application before driving on it. Again depends on type of sealer (ie. epoxy...). concretenetwork.com has a lot of good info as well. Good luck.
Is a hot dog refreezable?
Yes it is, as long as it is not expired during it's time of refrigeration prior to freezing.
Can frozen mango cause microbiological food poisoning?
If it was contaminated by microbiological pathogens prior to or even during freezing, it could cause foodborne illness. Freezing does not kill off the pathogens.
How do you keep concrete block walls from collapsing?
Prior to stuccoing the CBS you can install metal mesh or REBAR
Prior to placing concrete whatshould you accomplish?
take a few minutes to ensure forms are clean tight and braced
How do you prepare cement floor for vinyl tile?
Ensure concrete is clean, smooth and dry. Concrete should be first cleaned with degreaser to remove any residue. Use a self leveling compound if floor is not level or has some low areas. Fill any cracks or holes prior to using leveler. Allow leveler to dry overnight and seal concrete the following day to prevent moisture from wicking through concrete. Install flooring of choice.
How many days concrete has to be cured prior to steel erection What counts days or strength achieved by concrete?
the strength that it has gained is the main thing, but usually 5 to 7 days as a rough guide.
Why should hair products be removed from the hair prior to cutting?
Hair products should be removed prior to cutting
Is it ok to freeze raw dungeness crab?
Yes you can freeze your Dungeness crab meat raw as long as the crab has been cleaned prior to freezing. For more information check here: http://how-to-crab.com/freezing-whole-crabs/
What is the difference between cement and concrete?
Concrete is made from cement. Concrete has cement, rock and sand mixed with water. Cement is just the powdered hydrated limestone.Cement is a building material that is a powder made of a mixture of calcined limestone ( calcined: to Heat a substance so that it oxidizes or reduces) and clay; when cement is used with water and sand or gravel it makes what is referred to as concrete or mortar.Reinforced concrete means that there is a mat of rebar (iron rods) metal, and/or mesh added to provide extra support against stresses and is laid out prior to the pour of concrete.Grout is a thin mortar that can be poured and used to fill cracks in masonry, ceramic tile or brickwork.regular curingIt is critical to concrete's long-term durability that it be kept as moist as possible for the first seven days after placement. In addition, it must be allowed sufficient drying time before being subjected to freezing temperatures or to de-icing salts. Curing concrete properly requires the correct control of moisture and temperature and without proper curing, concrete may only achieve 50% of its potential design strength. The logic behind the practice of a seven day curing period rests on two facts:Cement, the "active" ingredient in concrete requires constant moisture to gain strength.If the concrete is kept moist for the seven day period, it will not only gain strength, but will also shrink less and produce fewer cracks.Curing can be assisted in a number of ways:Spray-on liquid curing agents and sealers.Water ponding or spraying a mist over the concrete.Coverings such as wet burlap, polyethylene, insulating blankets, etc.Leave forms in place.A liquid curing agent is the most effective and convenient method. The curing agent should be applied as soon as finishing is complete. Curing agents form a membrane on the surface of the concrete in order to retain moisture. Once the curing agent has been applied, no further working of the concrete can be done. Use a spray or roller to apply curing agents.According to CSA A23.1-94, curing is a mandatory part of concrete construction and requires moisture to maintain the concrete at 100% relative humidity and a minimum temperature of 10°C for a period of at least 3 days. This period is extended to a minimum of 7 days for the durability requirements of exposure classes F1, C1, C2, S1, and S2.cold curingConcrete can be placed safely throughout the colder months if precautions are taken. During colder weather, the mix should be adapted to the ambient temperature by heating the concrete, adding accelerators, and providing protection. during colder condition's, it is important to heat all concrete to meet the requirements of CSA and to maintain reasonable setting times and strength gain.Concrete generates heat during the hydration process, (the chemical process by which cement reacts with water to form a hard stable paste). Hydration is affected by initial concrete temperature, ambient air temperature, the dimensions of the concrete and mix design.The temperature of the concrete during and after placement is critical since concrete sets more slowly as the temperature drops. Finishing and form removal may be delayed in cool weather and strength development can be impaired if appropriate precautions are not taken.whenever possible , if not always, do not place concrete on frozen ground, on snow, or in freezing weather. If concrete freezes while in a saturated condition, surface problems like scaling, spalling or cracking can arise due to the expansion and contraction of frozen water inside the concrete.During freezing weather, water curing of concrete should be terminated 12 hours before the end of the protection period.Do not use a curing agent if there is any chance that the concrete will freeze during the curing period.Protect concrete from freezing temperatures for 3 to 7 days after placing.Leave forms in place as long as possible. Corners and edges are most vulnerable (cover and heat if necessary).Protect flatwork by covering and heating, or using insulated blankets, or covering with plastic and straw.This information has been provided to assist you .For a complete review of cold weather concrete practices, please refer to CSA A23.1 -- 94 Section 21.
Prior to using an AED you should?
Prior to using an AED you should confirm the absence of a pulse.
