Congolese construction - mixing concrete

In America, working with concrete is no problem. When we want some on a
job site, we call the concrete company and say "I want 18 yards" and
they ask about kinds, additives, and figure out a delivery schedule.
When you want concrete in Congo, you mix it by hand, on the ground, with
a shovel.

It all starts with a pile of sand on a fairly "flat" surface. This pile
of sand could be a bucket, or a truck. At David's house, it's probably
a pile equivalent to 5 wheel barrows full of sand (the quality
contractor wheel barrows, not the garden ones). Then you need cement.
The cement comes in 50 kg bags and they never use enough (but that's
another blog post all together). The fairly cone like pile gets a spot
hollowed out and a bag is dumped in the hollow. They go to another spot
and fill in another hollow with cement. This continues until the pile
is sand with cement in pockets on the surface. Now, fun part number one
begins.

With shovels and lots of labor, they mix the cement and sand. They turn
the pile, flip it over, move it from side to side, and in general, act
like kids playing in the dirt until it's all a uniform color. depending
on the size of the pile, this is a lengthy operation, and is quite fun
to watch (although the workers don't always appreciate that). Once it
is a uniform color they know it's mixed well and they make it into a
circle shape about a foot or a foot and a half high.

Then they bring on the gravel. They bring this from the gravel pile
usually in small buckets (probably 2 gallons or so) and dump it, bucket
by bucket, onto the mix. They just dump it on top until they feel it's
enough gravel (the gravel is usually bigger than anything I've ever seen
in the states as well). Once all the gravel is on the pile, that begins
fun part number two.

I see what you're thinking, but you're wrong. They do not mix this like
they did the sand and cement. They get a hose of water (or lots of
jerry cans) and pour some water onto one small part of the mix. They
then mix the cement/sand/rock mixture only until that water is used and
then they use that part of the concrete. They then move next to that
section, adding more water and using shovels to mix the whole shebang.

They are complete with the concrete pouring when all the concrete is
used. It's not like the states where the truck empties the extra
concrete somewhere and cleans out. There is always something that can
use concrete. Something else standing by that is just waiting for
concrete. Something with it's hand in the air saying "pick me, pick
me." Any "left over" concrete goes here, and if it's not enough for the
extra job, oh well, it'll be finished another day. Hermoine Granger
would be proud of the walkway by the lake at Maji Matulivu which has
shot it's hand into the air more times than she has in all her classes
at Hogwarts.