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The answer is that concrete never cures completely. It is always hardening a little bit more each day. The way concrete hardens is a function of the cement particles reacting with the water it is mixed with. As the cement bonds with the water molecules, the concrete gets harder.
Why would concrete not dry?
The reason that concrete doesn’t dry out and then reabsorb water later is because water isn’t leaving the concrete at all. It’s reacting with it and becoming part of the concrete form. Concrete continues to set and cure for months and years, increasing its strength over time.
Why does my concrete still look wet?
It continues to appear even after cleaning, and seems like a problem that never goes away. It is caused when water or moisture carries it from deep within the pores to the surface. Once the efflorescence has been removed, it is important to seal the concrete to reduce the movement of water and moisture.
Why is my concrete not setting?
A.: The three factors that you mentioned low temperatures, replacing cement with fly ash, and use of a water reducer may all have contributed to slow setting of the concrete. Don’t use calcium chloride accelerators because they can cause discoloration of decorative concrete flatwork.
Will concrete dry if too wet?
When a concrete mixture is too wet, it causes a greater amount of shrinkage during the drying process than is needed. As a result, the concrete has a great likelihood of cracking and for those cracks are likely to be a fairly good size. A watery mix actively reduces the compressive strength of the dried concrete.
What happens if concrete is too dry?
If it dries too quickly, the surface of the concrete will be weak, and will be subject to spalling. Spalling happens when a weak surface layer of concrete allows water to infiltrate. The water freezes and breaks up the surface of the concrete.
What does baking soda do to wet concrete?
Baking soda acts as a catalyst and promotes hydration of cement through hydrolysis reaction. An alkali silica reaction occurs within the cement milk to form alkali silica gel. This shortens the setting time, and curtails excess moisture.
How long does it take 4 inch concrete to dry?
Concrete typically takes 24 to 48 hours to dry enough for you to walk or drive on it. However, concrete drying is a continuous and fluid event, and usually reaches its full effective strength after about 28 days.
Can water seep up through concrete?
However, concrete is porous. No, water isn’t going to soak up like a sponge, but concrete does allow water to seep through when there is enough. Concrete also cracks, and those cracks will be the first routes of seeping water as it leaks through the slab.
Should you wet concrete while curing?
ANSWER: Keeping concrete moist helps the curing process. If too much water is lost from the concrete through evaporation, the hardening process slows down or ceases. Concrete continues to gain strength after pouring for as long as it retains moisture, but the longer it moist-cures, the slower the rate of strength gain.
Should I spray water on my concrete after it is poured?
To put it simply, the goal is to keep the concrete saturated during the first 28 days. The first 7 days after installation you should spray the slab with water 5-10 times per day, or as often as possible. Once the concrete is poured the curing process begins immediately.
How do you cure moist concrete?
DO spray new concrete with water. One of the most common methods for curing concrete is to hose it down frequently with water—five to 10 times per day, or as often as you can—for the first seven days. Known as “moist curing,” this allows the moisture in the concrete to evaporate slowly.
Can I drive on concrete after 3 days?
Your new concrete is designed to reach 90% of its full strength potential after 7 days, so feel free to drive your personal vehicle on it then. It will take additional time before you can drive or park heavy equipment or machinery on your newly poured concrete, so make sure to wait at least 30 days.
How long will concrete last?
Modern concrete—used in everything from roads to buildings to bridges—can break down in as few as 50 years. But more than a thousand years after the western Roman Empire crumbled to dust, its concrete structures are still standing.
How do you know if concrete is dry enough to paint?
Moisture will prevent the primer and paint from adhering properly. An easy way to tell whether the floor is dry enough is to place a small piece of kitchen plastic wrap (about 12” square) to the surface of the concrete floor. Seal all edges with tape. Wait overnight and then check the plastic.
What happens if you add too much water to quikrete?
NOTE: the more water that is added to the mix the weaker it becomes; adding one extra quart of water per 80 lb bag can reduce the strength of the concrete by up to 40%.
What if my mortar is too wet?
Mortar that is too wet will run out between the joints. If it is too dry, the bond will be weak. Let the mortar stand for about 5 minutes, then mix it again before using it. If the mixture is soupy, reduce the amount of water.
What happens if you add too much water to cement?
Effects of too much mixing water Lower compressive strengths. Segregation of the concrete mix under certain conditions resulting in variable quality throughout the concrete mass. Cracking – with too much water, there will be lower tensile strength, and a tendency towards high shrinkage and subsequent cracking.
Is it OK to rain on new concrete?
Pouring Concrete in Rain. Pouring concrete in the rain can compromise its strength, increasing the tendency for dusting and scaling to develop. Once the damage is done, it can be hard to rectify and will often ruin the appearance of the finished surface. Don’t let it rain on your parade.
How long should you keep concrete wet?
How long to keep it wet depends on temperature and the mix—you want it to have reached sufficient strength on the surface. Typically, about 7 days is sufficient with Type I cement—less in warm weather.
Does vinegar dissolve concrete?
When it comes to cleaning stone, concrete, and ceramic tile floors, leave the vinegar under the sink. Just like with stone countertops, the acid in vinegar will strip away the protective sealant from stone tiles, making them look dull and leaving the surface vulnerable to etching and pitting.
How do I get my concrete white again?
Apply vinegar or bleach to the discolored areas. If you use vinegar, do not dilute it. Pour it onto the concrete and scrub it into the surface with a scrub brush. If the discoloration starts to fade, repeat until it disappears completely.
Will straight bleach harm concrete?
Bleach is safe to use on concrete. When applied to concrete, bleach does not harm the sturdy material. It also disinfects concrete. When using bleach, work in a well-ventilated area because the fumes from bleach can be overwhelming.
