Mix Your Own Cement
Learn to use basic cement building materials:
Welcome to our article (41), mix your own cement
Dear readers, this is going to be a long article, because we want to explain how to mix concrete, in several ways, we are also going to mix other things as well, and the name mix your own cement covers them all.
The reason why, we are writing this article how to mix your own cement, it is because we want to pass our knowledge of how these things are done. So, we are writing this article for those people that are willing to do building work themselves, but they need a bit more knowledge to give them the courage to do it; and above all for those people that live in poor countries, where building skills and material are scarce, therefore, they need some knowledge to try building themselves, as long as they can buy Portland cement and/or lime to mix it with; so, this article can be D.I.Y article.
This article “mix your own cement” (concrete) is going to be a long and detailed way of how to make concrete from scratch, using Portland cement and other basic materials, we will also describe how to mix mortar for the bricklayer and cement plaster, just by using the most basic building materials, by mixing them with Portland cement and/or lime. We will describe how these things were/are done, because we believe that it is helpful to know that.
We must say that today building anything has become easier, because most things that we need are ready made for us to use, provided we are living in a city or large town in the western world and in many other parts of the world. In our case we are talking about how to use cement and the things that we can do with it. So, let us suppose that today we need concrete; we can order it, and have it delivered whenever we want it.
But these things were not so in the past, in the past people that were building had to have their own skills how to mix their own concrete, how to mix their own mortar and other things, and sometimes they had even to find the building materials themselves, before they could start to build anything, they were not easy times and people in the know, kept their knowledge for themselves. But today it is different, the knowledge they had and kept to themselves has become insignificant compared to the things that we know and do; so, to keep any knowledge for yourself is the wrong thing to do, because it is not going to help you, but it can help other people if it becomes common knowledge, but this knowledge can be useful for those people that don’t know yet, because they happen to be in a different part of the world, so, they would like to know.
Therefore, this article is being written, in the hope that our articles can help those poor people that are not aware that they can build a better place for themselves, if they learn to recognize the basic materials they need to use for building a place for themselves. Most of the building materials that we are talking about are available anywhere in the world, because they occur in the natural state as they are part of this great planet earth, so, what are those building materials you may ask? And how we mix them you may want to know, so, here is a link from YouTube that shows you how to mix concrete;
We would like also to point out with these photos here under what is available in Brisbane Australia, and then we will talk about those building materials that occur anywhere in the world.
Ready mix concrete In Brisbane
Cement and other materials
What are these building materials?
Anyhow, I know a lot how to mix concrete, since I have mixed it by hand and with a mixer hundreds of times, so, let us see these building materials and how to use them.
First, let us see what these materials are, then we will take you through how to mix them. Today you can buy these building materials ready to mix, and all you need to do is to add the right amount of water and mix them, but here we want to start everything from scratch:
In building anything with cement, there are five main sort of materials that we need to recognize, before we start mixing our batches of whatever we want to mix, they are; bricklayers’ loam, plaster sand, river sand, gravel, and Portland cement; with these materials you can build anything, some of these materials sometimes are called with different names, but, let us describe what these material are like:
Bricklayers’ loams is a very fine sand, some of these fine sands could be a tiny bit sticky and when it is wet enough you can almost make a small ball in your hand, but it will always collapse as there is not enough sticky material in it, but if you add the right quantity of cement and water (and perhaps something else if required) it is easy to lay bricks.
Plaster sand is very fine sand but not as much as bricklayer’s loams it does not stick together by itself, therefore, it will stick together only when you add cement and water to it, this type of sand is used to plaster the walls, and can be used to lay concrete blocks it is ideal to use this sand provided it is very fine, in this part of the world we call this Besser sand.
River sand, or washed river sand is a type of sand coarser and thicker than plaster sand, as the name suggests it comes from the river, in this parts of the world because Brisbane river is salty water it is washed and sieved, but it is possible to find deposit of this sand in some rivers that can be used straight away, sometimes this sand can be used by itself to lay a top layer on a fresh laid concrete, but its use is mainly used to mix it with gravels to make concrete.
Gravel or gravels are small stones again these small stones can be found in or near the rivers; in most places if there is proper supplier, gravels are graded so one can order them as they are required, and this is what we need to make good concrete. But if you happen to be in the middle of nowhere, they don’t need to be graded properly to use for concrete and one could use a mix of different size provided you know what you are doing. But one must be careful that this ungraded building material is free from silt and organic stuff.
Today of course building people rely more from the specialized suppliers, and they order through these suppliers what they need. You can even buy bags of ready mixed materials that you can use just by adding water. These materials are good to use, if you have a small job to do, but they become expensive to use if you have a large job.
What we have described above are the main materials required to build most cement things, of course, you must know how to use them, and that is what we are going to write next.
This is a retailer deposit for supply of cement
This is a description of cement and other materials
Since there is not enough room to describe the cement properties under the photo above, let us describe it here; cement is like the glue that when mixed with sand, gravels and other aggregates makes these materials stick together. The word “cement” can be traced back to the Romans, who called this “opus caementicum” to describe masonry that resembles concrete. We dare say that the Romans used burned limestone which when you add water turns into hydrated lime and also they used something called pumice that was collected from some part on Vesuvius it was a sort of cement that when you added water would become harder than if you just used lime, this is more or less how I have been told. As you can see there are two main bonding materials that can be used to make concrete and mortar.
In this retailer supply shed above there are several ready to use cement product, so, beside bags Portland cement there are bags of hydrated lime, ready bags of concrete blend already mixed with cement, there is read to mix mortar and ready to mix plaster and other things. These ready mixed materials become costly when you must use a lot of it.
So, the cheapest and best way is to mix your own cement, or when the job is big then the best way is to order premixed concrete. If you need mortar or plaster, you must mix your own from scratch or pay the price of the bagged premixed materials.
Mixing your own concrete from scratch
Because I am an old tradesman, I have been asked a few times the following from some friends.
We want to mix some concrete ourselves; can you please explain us how to do that? We don’t have a mixer and we want to learn how to do that using the tools that we have; we have a couple of shovels and buckets a wooden float and some other small tools. We are a couple of strong blokes and we do not mind doing hard-physical work, it will be a pleasure to do some useful exercise, so, tell us how to mix concrete?
Okay, since you do not mind working hard, I will be glad to tell you how to mix your concrete by hand. Now, let us assume that you have the material on site, and that you are ready to mix your concrete. To mix concrete by hand, you need a flat platform where you can mix your concrete, this platform does not need to be made on purpose, all it is needed is a hard surface, perhaps a slab of existing concrete can be helpful or anything at all, as long as this surface is not loose, because you don’t want to mix the soil with your concrete.
To make is easy, we must assume that the bloke that sold you the building material, has sold and delivered some concrete blend. Now what is concrete blend, you are wondering; so, let us explain, concrete blend is gravel and river sand mixed together approximately two part of gravel and one part river sand, so, you don’t have to mix them anymore, it is ready to use.
To make normal concrete you need to mix by volume six containers of concrete blend to one container of Portland cement, depending on the quality of the concrete blend this may vary, so what we do next; we know that we need a lot of concrete, so, you measure say twelve bucket of concrete blend and put that on our platform, then you measure two bucket of cement to mix with the blend. These are the quantities to keep in mind, (6 to 1) this is a small batch of concrete, and you can make it bigger or smaller, if you keep that 6 to1 ratio. Sometimes this ratio may vary.
Now before you mix your cement with your blend; make sure that everything is ready, because once you start this process you must continue until you finish. Since everything is ready you can spread the cement on the concrete blend, after doing that you take your shovels fill them up and start turning your mixture around, by pushing the shovel under and turning it over, you need to turn your mixture a couple of time; say first from A to B and then from B to A, so, everything is in the same place, after doing that and you are satisfied that your mixture is mixed even, you can make a well in the middle of it, and add a bucket of water, if the water is absorbed quickly, then you know that you must add more water, if a fair bit of water remains in the centre then you can start folding the outside mixture in the middle, you can add some water as required, but don’t get carried away with adding too much water, because you need to add water bit by bit, you see this is one of those things that you learn as you do it and not before.
You have done all that and now you have a heap of this mixture half mixed; here again you take your shovel and turn your mixture from A to B while sprinkling some water on it, you may need to do this a few times sprinkling water and turning your concrete mixture from B to A and from A to B, you need to do this until you have an even mixture that it is well mixed. Now you have your concrete ready to place wherever you need to place it.
This is how mixing concrete was done in the old days, it was a hard job and it was not as accurate as it is today with the ready mixed concrete truck that can deliver concrete to your job whenever you need it, and all you have to do is to lay your concrete slab, or whatever you need to do. Anyhow, the description above, can be used if you are in the middle of nowhere, and you need concrete.
Learn the art of mixing cement
Learn to recognize and use the building materials when we mix cement;
Now, that we have written what are the building materials, and we have explained how to mix concrete by hand, this procedure can be applied to mix mortar and plaster etc. We have also explained how you can recognize the raw building materials.
You see, let us imagine that you need concrete, you live in the middle of nowhere and you have only a few tools, but you now a faraway place where you can go and buy Portland cement; you are not going to buy anything else at that place, because it is too far, it will be costly to bring it in, so, the rest of the concrete materials you are going to find near the river banks. I know it is like going back in time a hundred years ago, but there are parts of the world that are still that far back. Therefore, learning how to recognize the basic building materials for making concrete, and then mixing concrete by hand can still be useful today. So, we are writing these articles, hoping we can help any do it yourself small owner builders.
Now, we have to add that what we are writing here is how we have done these things, and we know they work, however, it is only our view and they work well in all minor jobs, but if you have large important jobs, you must consult the local experts.
Now let us see how we mix concrete with a mixer.
Mixing concrete with a mixer
Okay, let us make this clear, there may be several ways how to mix you concrete; you can mix it on the ground, as we have described above, you can mix concrete in a wheelbarrow, if you have a wheelbarrow with a good tray, or you can mix it with a mixer which is helpful to have. But what are the different procedures when you mix, in order to achieve the best result with the least amount of time and work:
The greatest difference for mixing concrete and also other cement materials is mainly this: when you mix by hand you can achieve the best result by mixing the materials with the cement before you add water, as this helps to make a more even mixture quicker: But when you use the mixer you don’t need to do that, in fact, you can have better and quicker result, by following this procedure hereunder:
Start the mixer and put in the mixer some water, approximately the proper amount to mix the whole batch, you know how much water to use once you have made a few batches.
Now before we proceed to mix, let us talk about the water amount. On building sites, it is near impossible to tell you how much water you need exactly, due to the fact that the materials you are using contains an unknown quantity of water, therefore, the quantity of water varies, you see, the wetter the materials are, the less water you need and vice versa if they are dry.
Now, let us assume that because you are new at doing this job, you are using a dry small bucket to measure the quantities of the building materials; in this case you have gravel and river sand in separate heaps, you know that this concrete is going to be mixed 6 to 1, but overall this batch you are going to mix 8 small buckets of gravel four of river sand and two of Portland cement:
Now the quantities above is how the best and strongest cement can be achieved, with a minimum of Portland cement used; very likely these quantities are written in the specifications, if you have any specification written, and the ready mix people use those amounts and have a perfect concrete, because the concrete mixer will mix it well and as dry as possible. But by experience on building sites, we use a bit more river sand and a bit less gravel, as this makes it easier to work with overall.
Now let us go back to mix our concrete:
So, after you have poured the water into the mixer, you put one single bucket of gravel and while the mixer turns put the two small bucket of cement into the mixer, the cement in the mixer will immediately mix in the water and the first bucket of gravel will make sure that it does not stick to the mixer, because it will cut though any lumps easily, now you add four buckets of river sand, and this again will mix very quickly and become like a thick cream, all you have to do next is to add the other seven bucket of gravel, once you have done that you only need to wait a little bit for the mixer to mix it properly and your concrete is ready. Now all you must do is to tip your concrete in a wheelbarrow and take it to the place you need to concrete.
This is the quickest and best way to mix concrete in a mixer, as I have done it for thousands of times, but I need to say that on building sites, where there is plenty of cement to mix and the workers have to try not to injury themselves, by lifting hundreds of bucket full of material all day long, they use to measure the materials by the shovelful, but you have to be an expert at doing that to get everything measured right. I hope this description of how to mix concrete is clear enough.
Before we leave this concrete discussions we want to add more information; you see, concrete in itself is very strong in compression, but is lacks strength under tension, so, to make concrete very strong and last a very long time you need to use steel in the concrete; here is a link that will help to understand some of these issues.
Mixing mortar, plaster, or cement topping.
Now that we have described how to mix concrete by hand and by using a mixer, the same ways can be used to mix mortar and/or hard plaster or cement topping etc. So now, we do not need to explain step by step how to mix them, but we will describe only the different amount of things that are used; but try to remember that when you mix by hand, it is a lot easier to mix the dry materials first and then add water, but when you use the mixer it usually is better and quicker to start with the water first.
To mix mortar for the bricklayer;
Just by using brickies loams and Portland cement, this mixture by volume is most likely 4 part brickies loams to one part Portland cement, but it could vary from (3 to 1) to (6 to 1) the aim here is to give the bricklayers what is easy to work with, and at the same time you don’t want to make the mortar a lot stronger than the bricks when it dries, and you don’t want to make it too weak for the job you are doing, so, it makes sense to see what the bricklayer reckons is good enough for the job; sometimes when making mortar you can replace part of the Portland cement with hydrated lime, plus other things to make the mortar easy to work with.
Mortar for cement blocks
The mortar for cement block is usually three parts fine plaster sand and one-part cement, it is a bit different from the brickie’s loams, as it is thicker and stronger and very close to the block’s colours when dry.
To mix cement plaster to plaster walls;
This mixture is usually 3 part plaster sand and 1 part Portland cement, in some countries where lime is easier to have than cement it can be made by using a mixture of lime and cement for the interior, we believe that there are a lot of old places that they have used lime only, the cement mixture is used wherever it is too wet.
This mixture is usually 3 parts river sand to 1 part Portland cement; it can be used straight on the cement if it is still green, but when the cement is dry you need to make sure it is clean and rough for the cement to bond, you may have to use tools to indent the existing concrete, then you have to wet the cement and also you may need to use some cement bounding agent and/or paint to concrete with this cement glue called Weldbond or Bondcrete or whatever and place the topping cement according to the instruction supplied, if these concrete glues are not available, you have to wet the concrete that you have to lay the topping on, then make some slur of water and cement and somehow work it in with a brush as if you paint the concrete, and before this starts drying lay your topping on it.
These three mixtures plus the concrete are the main things that are required when we build with cement, of course, for those people that do not know how the different materials look like, is still hard to understand the hole procedure, but if they read a few times what we have said, they should have a fair idea of what we are talking about. Anyhow, I have described several things already, but I think that I need to describe how to mix mortar with lime only, as it was done in the old days and here I am not talking just hydrated lime that you can buy at the hardware store, but I am talking about quick-lime as it comes from the kiln and slacked lime.
Lime use in building etc.
Quick-Lime and slacked or hydrated lime
Today when we talk about lime, we see a bag of white powder that we buy at the hardware store, we know that we can use this powder to replace some cement when we make mortar, but we don’t know much more than that, But lime is a lot more than just a white powder in a bag, because lime is one of those materials that has been and is being used a lot in many ways, its’ largest use is in making mortar for the master builders, but it has other uses also. So, let us talk about lime and where it comes from, so that we can understand things about lime and its several uses, of course, here we are mainly interested about its use in the building industry for making mortar etc. But there is more to say about lime, but before we do that let us check out how the Wikipedia explains quick lime etc. Where you can find a lot of information about lime if you care to know, click on the links.
From the Wikipedia:
Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely usedchemical compound. It is a white, caustic, alkaline crystalline solid at room temperature. The broadly used term "lime" connotes calcium-containing inorganic materials, which include carbonates, oxides and hydroxides of calcium, silicon, magnesium, aluminium, and iron predominate, such as limestone. By contrast, "quicklime" specifically applies to a single chemical compound.
Quicklime is relatively inexpensive. Both it and a chemical derivative (calcium hydroxide) are important commodity chemicals.
Calcium oxide is usually made by the thermal decomposition of materials such aslimestone, that contain calcium carbonate (CaCO3; mineral calcite) in a lime kiln. This is accomplished by heating the material to above 825 °C (1,517 °F), a process calledcalcination or lime-burning, to liberate a molecule of carbon dioxide (CO2); leaving quicklime. The quicklime is not stable and, when cooled, will spontaneously react with CO2 from the air until, after enough time, it will be completely converted back to calcium carbonate.
Annual worldwide production of quicklime is around 283 million metric tons. China is by far the world's largest producer, with a total of around 170 million metric tons per year. The United States is the next largest, with around 20 million metric tons per year.
As we have said, lime has been used for a very long time its use could be prehistoric, nobody seems to know when it was first used in making mortar and plaster for buildings and for other things, it was/is used even to disinfect places, when there is no much else to use, and I know that there is a lot more to say about the use of lime even today; up to the time when I was young it was used even to whitewash the walls in spring once a year, after a long winter all the walls were darkened with smoke, because if you wanted to keep warm you needed to light a fire in the chimney, so, the smoke of the fire would find the way into the rooms instead of going all up the chimney, I am pretty sure that even today this is the cheapest way of cleaning rustic building, as, it is one of the cheapest ways to make everything clean. But let us tell you it’s use as a building material to make mortar.
From quick-lime to hydrated lime
From quick lime to slacked lime the old ways
Here we are talking about the late forties and early fifties, when I was young learning what was happening around me, so, hereunder we will be writing about what I saw and learned at that time about lime products and its uses.
In the town where I come from in southern Italy; in the early fifties when there was a new building to be build or alterations to existing buildings to be done, one of the first things we would see was that the master builder would get ready a good supply of slacked lime, because this was one of the most important building materials he needed to do the job. In those times bagged hydrated lime and cement was very expensive, and bagged cement has a short life shelving span, as it reacts when humidity infiltrate the bags, therefore, most people or builders that needed to build used lime wherever they could; they would buy quick lime and get it process immediately on delivery themselves or with the help of the people that delivered it, of course, one needs to know how to do that, because it is dangerous while you are doing it. Now, let us see how it was done, and then we will tell you where else the lime was used.
Anyhow, the master builder before delivery had to build a square wall like a box, and in this large box he would process the quick-lime, because the quick lime cannot be held the way it is for any length of time, because it reacts to humidity and violently to water, so, it is necessary that it is turned into slacked lime as soon as possible after delivery.
Okay, the cart or the lorry is on the way, so, the master builder gets his worker to start filling the pit with water, and when the quick lime arrives they start carefully throwing this burned lime stones into the pit in very small quantities, as soon as the quick lime comes in contact with the water it reacts and the water starts boiling, everybody is banned to approach the pit accept the people that must work there, and they ware some protective gear, because it is dangerous to handle quick-lime and around the pit, this process goes on until all the quick lime is thus treated, once they have done that it is left to cool down for a few days; after it has cooled down it is a lot less dangerous, but still you need to be careful near the lime pit. You see, the lime pit is now filled up with slacked lime, which looks like curd when you make cheese, but it is still dangerous and it can easily kill you if you fall in it, its contend must be handled with caution, but anyhow the slacked lime is now ready to be used, this is how the builders used to get ready the lime to make mortar. Now to use this lime to make mortar is different from using bagged hydrated lime or cement; so, we are going to tell you how to make mortar with slacked lime.
How to make mortar with slacked lime
This is how I know it was done in the old time, perhaps for thousands of years, anyhow, let me describe the procedure. Let us suppose that you have the slacked lime in the pit or in a container; you have brickies loams or fine sand, so, let us start:
Start by making a hip of your sand on a platform; now that you have done that, make a well in the centre and place your slacked lime in it. The quantities in here may vary a lot more than when we use cement or hydrated bagged lime, because the slacked lime can be as liquid as thickened cream to as compact as feta cheese, so, you have to learn as you go about the quantities, but if you have mixed mortar before, you soon work it out yourself, or if there is any tradesman that is going to use the mortar he can tell you just by looking at the mortar being done, whether you need more lime or more sand and water etc.
Okay, now that you have the lime in the middle of the sand, with a Larry start pushing this devise up and down through the lime by adding a bit of water as needed and slowly mixing some sand with the lime; you need to do this until you have mixed the whole lot evenly. This is hard work but that is how it was done when there were no mixer and no bagged hydrated lime around.
Here we need to note that this mixing of slacked lime to mix mortar is completely different from mixing other mixture, because the slacked lime is already wet, and it is like a paste.
Now, let me talk about, lime use in farming.
Lime use in farming
You know, lime is a very useful commodity, in fact they are countless places where we can use it, I only happen to know a few of them, so, let me say a few things about how we were using lime in our small family farm at the time when I was young, just the way I remember it:
We would use it like the builders use it when we had to repair or replace a few stone that were falling apart in the old stone building, so, instead of using clay like the first time, we would mix a small quantity of mortar using lime and sand; then, we used lime to whitewash the farm house, the stables, the pig stay, the chicken coop and sheds or other buildings near the farm house once a year in spring.
We could use it to disinfect stagnant water ponds that showed signs of vermin, or the water were too dirty, so, we would dilute some lime in water and then pour it in the water ponds, and next day the ponds would be clean, as the lime would kill the vermin and would make the water clear because all the dirt would sink to the bottom of the pond; you see, in our small farm we used to have a kitchen garden, so, we would dig up a few ponds beside the garden that would feel up with water during winter or when it rained, we used this water to water the plants when the soil was becoming too dry for the garden plants to grow.
In the farms of those days lime was also used to spray vines and trees, sometimes there were diseases that could be controlled by applying a coat of lime to the trunk of those trees; but there is one thing that always comes to my mind; it is when we were spraying the grape vines with a copper sulphate and lime, we would have two containers one with diluted copper sulphate and one with diluted lime, some people used to spray first with copper sulphate and then with lime, so that they would help each other to kill the mildew, but my grandma had worked a way how to avoid this double spraying and it worked thus;
In those times it was not like today and even the vine spraying pump was a devise that you would put on your back, and with a handle that you moved up and down you would spray your vines and trees as well; this devise could hold about three gallons of liquid, so, every now and then you needed to fill it up; as I have said we had two containers one holding diluted copper sulphate and one with diluted lime; (of course you had to know how much diluted you had to do your mixtures but that does not mutter here this time) anyhow, when the pump was/is empty you would go to these containers to fill it up: here is my grandma way to avoid to spray twice, when filling the pump, first of all you had to make sure than the mixture were well stirred, then you would put the copper sulphate in the pump and at the last minute you would add the lime, and immediately start to spray. This was my grandma way and it worked because the mixture would not have time to settle down and become stale. There you are this is just another way of how lime is useful in the farms.
Anyhow, I think that this article is too long, and I have said enough about how to mix your own cement or mortar, about lime and lime use in farming, so, see you next time with our article, bricklaying is competitive.
Some links about building with cement
- Australia affordable houses
Building affordable houses for sale is usually good business, when they sell easily; sometimes the builder has to sell at cost in order to continue building more houses, this is good for the buyers.
- House building in Brisbane
Let us talk about houses building, some reasons why there are different ways of building houses in the whole world and House building in Brisbane in the sixties, brick bases under timber houses.
- DIY brickwork
Thinking of laying bricks yourself, then read this hub it could help. DIY brickwork; Getting ready to lay bricks; making sure that we start the brickwork level, and Laying bricks on a sloping site.
- DIY Retaining walls
We are going to show you several types of retaining walls and how to build them, some of them briefly and other step by step, so that you could be able to do it yourself, if you like.
© 2013 F-Menchise