Many hours of planning need to go into a project before anything can begin. Machinery such as cement mixers and concrete vibrators will need to be leased or purchased, and any time that they are not operating is wasted money. One of the biggest expenses in a project can actually end up being cement and concrete pours, but this isn’t simply due to the amount you have to spend to get the ingredients from a shop.
From cement mixers constantly rolling around to the generators it takes to power them, whether these are owned or rented, anything sitting by not helping towards a profit is an expense. There are many machines that are needed in a concrete pour and if they aren’t working then neither are you. After each pour you need to ensure that your cement mixers are properly cleaned and cleared of debris and your generators are sprayed down with an air duster to dislodge dust.
Cement mixers are integral as they will mix all your aggregate together as well as keep it constantly moving, thus preventing the chemical reaction from beginning. Cement mixers can do a job that used to take many men and were extremely tiring, so they are essential for any big pours or frequent smaller pours. By obtaining cement mixers and keeping them in proper working order you are already saving yourself several days in the overall concrete process.
If you need tried and tested cement mixers for your next project, then check online at BSPOWER. They’ve got great deals and can inform you on everything you’ll ever need to know about cement mixers, cement, gravel and sand types to make sure your next pour lasts decades. Once you’ve checked the catalogue and got all your new machinery ready, it’s time to take a look at what you’ll actually be pouring.
Concrete is truly a strange and fascinating thing to watch roll around and around within cement mixers. It is so hard to imagine that the goopy, liquid substance sloshing around forms some of the strongest foundations of human infrastructure. Concrete has a complex chemical reaction that uses the cement compound and water to bind the dirt and gravel together if given enough time, but if time is not given and for example a floor is laid on concrete that has not finished curing, the escaping moisture from the concrete can actually damage the newly laid floor as well as forming structural weaknesses within the foundation.
But time isn’t always a luxury that one can afford, especially on a construction site. If plans don’t go exactly to schedule you could have a line of cement mixers and other machinery just sitting and gathering dust while you just constantly water and watch concrete dry. If you don’t feel like debating the paint versus concrete viewing experience, this article has some tips for you the next time you need a fresh concrete pour to cure slightly ahead of schedule, while still maintaining all of its structural integrity.
Concrete is quite pliable before it is completely cured so sometimes speeding it up can be beneficial in ways besides helping with scheduling. A faster cure obviously means the concrete is exposed to damage for less time as well as less man-hours spent keeping it moist. Be cautious however, if you are going to attempt to speed up the cure of your concrete then even more care than usual is needed to ensure there are no costly mistakes.
Difference between Curing and Drying
Concrete that is curing and concrete that is drying are actually two different things. Curing is the process that begins immediately after concrete has been poured and it begins to harden, the cement bonds with the water and becomes porous. This process can take up to 28 days under normal conditions, however even after this period of time has ended concrete will actually continue to harden and dry for a long time.
Drying is when the water actually evaporates through the surface of the concrete. As more and more water evaporates, water from deeper down in the pour will start to move up to the surface to replace the evaporated water. If the surrounding air can hold moisture, evaporation will continue.
A general understanding is that concrete that is 1 inch or just over two-and-a-half centimeters thick will take 30 days to fully dry, with another 30 days for each added inch in a pour. Drying can also happen too quickly in concrete during a cure, as excessive heat or winds can cause the surface of a concrete pour to turn back into powder or start cracking. This is chemistry after all, so if you are attempting to speed up any reaction then you will need to be careful and also be ready for any possible consequences.
Speeding up the Cure
Firstly before you even start loading the cement mixers you need to lay out everything you need in all the correct ratios. Too much water in your initial concrete mixture means more moisture will be left over after curing and more time spent waiting. Also be sure to check what aggregate you are using, if you can load a bit more cement in without causing shrinkage and cracking this can reduce the wait time greatly.
If you are using a lightweight concrete aggregate perhaps consider switching to something else, as these absorb a lot of water. Some synthetic aggregates have been developed to absorb less moisture and dry out faster. Finally avoid using any sealing agents as even though this can help with the cure by keeping moisture in , if not removed they can then trap moisture and greatly extend the drying time.
An obvious but sometimes overlooked tip to help speed up your concrete cure is to make sure you have some warm and sunny weather lined up for the next couple of days. This will make the moisture in the concrete evaporate faster and speed up the chemical reaction. With this and with anything else mentioned in this article that increases temperature, ensure that extra attention is paid to the moisture level on the surface to avoid cracking and drying out.
A chemical solution to the problem would be to go to your nearest hardware store and get your hands on some calcium chloride. Calcium chloride is an accelerating compound that needs to be added to the concrete mixture before it is poured and when it is still wet. As with everything dealing with cement mixers, cement and concrete, ratios are extremely important so make sure to read the instructions carefully and adjust for your specific circumstance.
Once your concrete has been poured, covering it with a plastic sheet or tarpaulin is always recommended as not only will this trap moisture and raise the temperature, it will also help keep small animals and debris from causing small damages to the surface. If working indoors, a small heater can also be added to further raise the ambient temperature and speed up the curing process. Do not position the heater in a way that only a portion of the surface is receiving direct heat as this will cause marks or damage, rather point it so the entire room is warmed.
Speeding up the Dry
Once your concrete has cured and hardened you can begin helping it dry quicker. The first step would be to immediately close off the area if you haven’t already done so to prevent any additional moisture from seeping in. If a space is fully enclosed, this will also allow you to control the level of humidity in the area and speed up the evaporation process.
If the ambient humidity is too high the water on the surface will actually have no reason to evaporate, therefore in some circumstances an HVAC (heating, ventilation and air conditioning) system may be needed. These systems can use heaters and fans to raise the ambient temperatures as well as remove humidity thus greatly increasing the water evaporation. If an entire system is not needed, as mentioned above a small heater as well as a portable humidifier can be bought or even rented.
Measuring Concrete Moisture Level
There are actually quite a few ways to measure the moisture level of concrete and thus see how your drying is progressing Some methods are very accurate but come with their own costs and complexities whereas others are very simple but give no numerical reading of the moisture level. Below we will discuss three ways that range from DIY to engineering graduate.
The simplest way to see if concrete is still drying seems a bit silly but can actually be very useful when you don’t want to incur additional costs on a project. All you will need is some clear plastic sheeting, tape and scissors and you’re ready to go. Cut the sheet into several 500 cm by 500 cm pieces and make sure there are no holes for air or water to escape through.
Next you need to lay the tape down in any of the main areas you want to test or will possibly lay flooring and secure it down tightly with the tape on all the edges so no air escapes. Make sure that the surface where you are placing the plastic is dry so you don’t waste your time. Wait at least 48 hours and then inspect all the pieces of plastic by peeling them off and feeling the underside, any fogginess seen means that the level of moisture that the concrete is evaporating is still very high and could cause damage to any flooring that is laid.
This test although simple is not accurate at all and only tells you that there is still water evaporating and not the actual level of moisture within the concrete. For more accurate measurements a calcium chloride test kit can be obtained that you will give a full reading of the amount of moisture that is still evaporating. This can be done a few times and if the levels are steadily dropping then you know that your method is working.
A final measurement technique makes use of probes that are either inserted into the concrete after a hole has been made with a drill or placed into the concrete during the initial pour. Because the probe is always within the concrete it can take several measurements over long periods of time and provide an average reading. If the levels remain constant or are decreasing too slowly then you will know that you need to try another method.
It’s difficult to say what method will work best as every situation is very different. Often you won’t want to just use one method and a combination of them will give you the most accurate data. Numerous tests should also be done to ensure that there wasn’t a variable, such as an indoor fan, that skewed the results. Once you have done a few readings and are happy with the results, you can say you’ve successfully finished your pour and get on with the rest of your project.