-----------------------------
Welcome to our blog, Mix your own cement. part two.
As we have said before, because this article was too long, we have split it, and this is part two, so, to make sense, you should keen in mind what we said in part one, and follow.
Mixing mortar, plaster, or cement topping.
Anyhow, in part one 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 parts 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.
Cement topping.
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.
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 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.
Slaked or Hydrated Lime
----------------------
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),[5] 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.[6]
----------------------------------
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.
To see more click on this link, Mix your own cement..
-----------------------------------