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Welcome to our blog, affordable rentals
and this post, making your own concrete
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Making your own concrete
This is a typical concrete mixer to mix concrete and mortar to lay bricks used on site, they can be electric or have a petrol engine.
Stepped foundations, when the ground is not flat it is necessary to lay the foundations with steps in them, so that the foundations are level for the bricklayers to lay bricks on them. See the picture this is a typical way of laying the foundations.
This is one short concrete stump with ants capping; These type of stumps could be used up to 2.4 meter high under the houses, after that a bigger stump would be required.
Making your own concrete
Making your own
concrete on site from scratch
Dear readers, this
post is the continuation of our last post, Australia affordable houses, where
we were talking about, how we build these affordable house in the sixties, when
I came to Australia, we had reached a point where we were about to explain how
we make our own concrete on site. Now, let me explain what is meant by concrete
in buildings and how it is made would be good to know; if during your life you
are going to do any sort of renovations, it would be useful to know how to make
your own concrete properly, so that you might understand what is required and
how and why it must be done in certain ways, you will find it written in this
hub. Some people might say here that today thing are usually done in a
different way, so why bother to tell us all this stuff about how to mix
concrete properly, when we can buy the concrete ready mixed by truckload, or in
bags and all you have to do is to add water to make concrete.
Here I would like
to say, that perhaps today in the big cities and large towns, you may not need
to know what I am going to write here, because most thing are ready made: but
anyhow, I am still going to write how concrete is made for the outback, and for
those people that happen to live in a poor country, and for them it would be
helpful to know how concrete is made from scratch.
Anyhow, it would be
helpful to know how concrete is made from scratch, because that is the only way
if you don’t want to make costly mistakes when you build something using cement
and other building materials. Therefore, let me tell you how we were mixing our
own concrete in the sixties and also what is usually required to do that and
how it is supposed to be done, if you want a good job done and the concrete to
last a long time.
By the way here we
need to clarify one thing as I am worried that some people might not be sure
what is meant by the word concrete, because usually they would replace it with
the word cement; on building the word concrete means all the element mixed
together able to harden to a solid consistency within a certain length of time,
therefore it has got to be done the right way.
One of the most
important things while mixing concrete is that the concrete should be well
mixed and to a workable consistency using the least amount of water possible,
because if too much water is used then the concrete becomes weaker, therefore
it must be done properly.
Usually concreting
and other jobs are done according to its specifications, you see any good firm
that makes building plans, which may be just a small house or something else of
more importance, and they have to writes also the specification how the job
needs to be done. In these specifications it will be written what material to
use how to use it and also the quantity and quality required. Therefore, to
concrete say a foundation for an average small house, the specification written
in those times could usually say that the concrete should be mixed to a
consistency at least 1 to 6; for people that knew this it meant that to mix the
concrete you should use 1 part of Portland cement 2 parts of river sand and 4
parts of gravel (aggregate) and mix it as required until an even consistency is
achieved. For the stumps usually would be a bit more cement than the
foundations. But I have to say that sometimes even these rules had to be
changed a bit depending on the material that could be delivered on that local
site.
Now let us say that
we are ready to start mixing the first batch of concrete, as we have made
everything ready, and everything has been delivered. To make concrete you need
at least four elements of materials plus clean water; 1 Portland cement, 2
washed river sand, 3 clean or washed gravel and 4 reinforcement steel rods, and
also it is helpful if you have a mixer if you have to mix a large amount of
concrete, because to mix by hand is hard work and the concrete needs to be well
mixed.
Now let us start
the mixer and make the first batch, while the mixer is turning around, the very
first thing you put in the mixer is water, one must be careful not to put too
much water to start with, it has got to be just enough to mix everything to a
certain consistency, so let us say that we put 8 litres of water (the amount of
water can be different, since it depends on the amount of water that is already
in the (sand gravel) aggregate) then we put in the mixer cement, next is the
river sand twice as much as the cement and then the clean gravel 4 time as much
as the cement; here the mixer is going around and mixing everything together.
For people that do
this job all the time it is easy for them to see if the concrete that is being
mixed has the right consistency required; if it is too dry just add a bit of
water and if it is too wet you have to add a bit of everything else. There you
are it is not too hard if you know how to do it.
What I have written
above here applies only to house building of less importance, for building that
are large and important the concrete needs to be to a very high standard and
specifications.
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Concrete requires team work
To concrete usually
requires team work
In order to
concrete well and do a fair amount of work on these houses you need a team. Our
team was usually three of us, I as builder labour, John as bricklayer and Con
the contractor who was a bricklayer and concreter. So I was usually on the
mixer mixing the concrete, one was with a wheelbarrow taking the concrete from
the mixer to the foundations that we were concreting and one was fixing the
concrete in place.
Fixing the concrete
for the foundation was physically the lightest job, when we were mixing the
concrete with this mixer on site, but it also was/is the most responsible job,
because while concreting the foundations first of all you have to make sure
that the steel rods reinforcement was in the right position, at the same time
you had to pack the concrete down and then the concrete in the foundations has
to be finished level, this was easy when the ground was level, but when the
ground was not level, it was necessary that some steps were made and they had
to be to gauge, which was equal to the thickness of one or two laid bricks or
more, or perhaps the thickness of a laid block, if blocks were going to be used
to build the walls on this foundation, whatever was going to be used to lay on
the foundations, we had to try to make an adjustment while we were laying the
foundations; therefore this was the job for the experts, at that time it was
not that hard, because mixing by hand even using a mixer was a slow job, so the
bloke that was fixing the concrete had plenty of time to do his job right.
What I have written
above is how we used to lay some small foundations in the early sixties, which
are much the same as we would lay foundations today, except that today we just
order concrete already mixed, but we have to be really ready with everything
and everything has got to be in the right place, because the concrete ready-mix
truck will unload its concrete very quickly, so there is no time to do anything
else except to fix the concrete at the right level as quickly as possible and
as required.
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Concreting stumps on site
Concreting stumps
on site
Now let me go back
again to the early sixties, when we were concreting these stumps on site, as
this is not done very much today, the reasons for this change it is because the
buildings have gradually changed in many ways and also today some of these
stumps can be made in a concrete factory and when cured can be delivered to the
building site, where the worker can erect them as required. There are other
reasons also and later on we will be looking at this also.
To concrete these
stumps on site we had some steel forms of various length, and these forms were
assembled together with steel pins, so we first of all we would assemble these
steel forms and then start to mix concrete, we had also make sure that the
stumps were exactly in the right place by using the marked profiles and tight
line between them.
In this case it was
an easy job for the fellow that is mixing concrete, but a lot harder for the
blokes that had to pour the concrete in the stumps formwork and make sure that
the stump was exactly in the right place and finished at the right height and
were also plumb (perfect vertical position). It was also necessary that some
reinforcing rods were placed in the right position with a purpose made devise.
These are how we made those onsite stumps in the sixties.
These concrete
stumps that we made in the sixties were better that the timber stumps that they
were replacing, because it was an improvement as they did not rot with the
passing of time and the white ants would not eat them, as they did with the
timber stumps. Here we could say that these concrete stumps on site were easy
to make, if you knew the procedure, in fact it was easier to make a set of
stumps than to fix concrete stumps made in the factory, as there was no heavy
lifting involved.
But although these
concrete stumps were easy to make, they would be hard to move to a different
position. So to anyone that is going to attempt to dig out these stumps to move
them to a new position, they better think twice because I tell you that the
part that is under the ground is a lot larger than the stumps at the top.
Remember what I said in our previous hub, we had to dig a hole sixty centimetre
dip in the natural ground, and at the bottom should be a level base not less
than forty centimetres square.
I believe that we
have said enough in this post as we have explained the work that we did on this
affordable houses and we will be coming back to talk about more building work
in our next post, house building in Brisbane. See you soon.
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